UBUNTU-CVE-2026-53080: Medium severity ubuntu/linux-hwe-edge vulnerability

Q: Who is realistically exposed to this issue?

Systems running one of the listed Ubuntu kernel packages are in scope when traffic control filters using the cls_fw classifier are configured. The demonstrated condition involves a shared TC block, a matchall filter with an skbedit action, and adding an fw filter while traffic is being processed.

Q: What level of access does an attacker need?

The supplied CVSS vector indicates local access, low privileges, no user interaction, and that an additional attack requirement must be present. The reproducer uses network and traffic-control commands to create interfaces, configure qdiscs and filters, and generate traffic.

Q: What is the impact if the issue is triggered?

The described behavior can cause fw_classify() to hit a kernel WARN_ON due to a NULL dereference involving an old filter. The CVSS vector rates availability impact as high, while confidentiality and integrity impacts are listed as none.

Q: How can I determine whether my configuration is exposed?

Review TC configuration for shared blocks that use the fw classifier, particularly where filters are added or changed while packets can traverse the block. The report specifically identifies a race in which an invalid filter may be published to the datapath before its change validation completes.

Published Jun 24, 2026

Updated

In the Linux kernel, the following vulnerability has been resolved: net/sched: clsfw: fix NULL dereference of "old" filters before change() Like pointed out by Sashiko [1], since commit ed76f5edccc9 ("net: sched: protect filterchain list with filterchainlock mutex") TC filters are added to a shared block and published to datapath before their ->change() function is called. This is a problem for clsfw: an invalid filter created with the "old" method can still classify some packets before it is destroyed by the validation logic added by Xiang. Therefore, insisting with repeated runs of the following script: # ip link add dev crash0 type dummy # ip link set dev crash0 up # mausezahn crash0 -c 100000 -P 10 \ > -A 4.3.2.1 -B 1.2.3.4 -t udp "dp=1234" -q & # sleep 1 # tc qdisc add dev crash0 egressblock 1 clsact # tc filter add block 1 protocol ip prio 1 matchall \ > action skbedit mark 65536 continue # tc filter add block 1 protocol ip prio 2 fw # ip link del dev crash0 can still make fwclassify() hit the WARNON() in [2]: WARNING: ./include/net/pktcls.h:88 at fwclassify+0x244/0x250 [clsfw], CPU#18: mausezahn/1399 Modules linked in: clsfw(E) actskbedit(E) CPU: 18 UID: 0 PID: 1399 Comm: mausezahn Tainted: G E 7.0.0-rc6-virtme #17 PREEMPT(full) Tainted: [E]=UNSIGNEDMODULE Hardware name: Red Hat KVM, BIOS 1.16.3-2.el9 04/01/2014 RIP: 0010:fwclassify+0x244/0x250 [clsfw] Code: 5c 49 c7 45 00 00 00 00 00 41 5d 41 5e 41 5f 5d c3 cc cc cc cc 5b b8 ff ff ff ff 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc 90 <0f> 0b 90 eb a0 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffd1b7026bf8a8 EFLAGS: 00010202 RAX: ffff8c5ac9c60800 RBX: ffff8c5ac99322c0 RCX: 0000000000000004 RDX: 0000000000000001 RSI: ffff8c5b74d7a000 RDI: ffff8c5ac8284f40 RBP: ffffd1b7026bf8d0 R08: 0000000000000000 R09: ffffd1b7026bf9b0 R10: 00000000ffffffff R11: 0000000000000000 R12: 0000000000010000 R13: ffffd1b7026bf930 R14: ffff8c5ac8284f40 R15: 0000000000000000 FS: 00007fca40c37740(0000) GS:ffff8c5b74d7a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fca40e822a0 CR3: 0000000005ca0001 CR4: 0000000000172ef0 Call Trace: <TASK> tcfclassify+0x17d/0x5c0 tcrun+0x9d/0x150 devqueuexmit+0x2ab/0x14d0 ipfinishoutput2+0x340/0x8f0 ipoutput+0xa4/0x250 rawsendmsg+0x147d/0x14b0 syssendto+0x1cc/0x1f0 x64syssendto+0x24/0x30 dosyscall64+0x126/0xf80 entrySYSCALL64afterhwframe+0x77/0x7f RIP: 0033:0x7fca40e822ba Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb b8 0f 1f 00 f3 0f 1e fa 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 15 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 7e c3 0f 1f 44 00 00 41 54 48 83 ec 30 44 89 RSP: 002b:00007ffc248a42c8 EFLAGS: 00000246 ORIGRAX: 000000000000002c RAX: ffffffffffffffda RBX: 000055ef233289d0 RCX: 00007fca40e822ba RDX: 000000000000001e RSI: 000055ef23328c30 RDI: 0000000000000003 RBP: 000055ef233289d0 R08: 00007ffc248a42d0 R09: 0000000000000010 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000001e R13: 00000000000186a0 R14: 0000000000000000 R15: 00007fca41043000 </TASK> irq event stamp: 1045778 hardirqs last enabled at (1045784): [<ffffffff864ec042>] upconsolesem+0x52/0x60 hardirqs last disabled at (1045789): [<ffffffff864ec027>] upconsolesem+0x37/0x60 softirqs last enabled at (1045426): [<ffffffff874d48c7>] allocskb+0x207/0x260 softirqs last disabled at (1045434): [<ffffffff874fe8f8>] devqueuexmit+0x78/0x14d0 Then, because of the value in the packet's mark, dereference on 'q->handle' with NULL 'q' occurs: BUG: kernel NULL pointer dereference, address: 0000000000000038 [...] RIP: 0010:fwclassify+0x1fe/0x250 [clsfw] [...] Skip "old-style" classification on shared blocks, so that the NULL dereference is fixed and WARNON() is not hit anymore in the short lifetime of invalid clsfw "old-style" filters. [1] https://sashiko.dev/#/patchset/2 ---truncated---

Affected Software

234 affected componentsFixes available

ubuntu/linux-hwe-edge*

ubuntu/linux-aws-5.0*

ubuntu/linux-aws-5.3*

ubuntu/linux-aws-5.4*

ubuntu/linux-azure*

ubuntu/linux-azure-5.3*

ubuntu/linux-azure-5.4*

ubuntu/linux-azure-edge*

ubuntu/linux-gcp*

ubuntu/linux-gcp-5.3*

ubuntu/linux-gcp-5.4*

ubuntu/linux-gke-4.15*

ubuntu/linux-gke-5.4*

ubuntu/linux-gkeop-5.4*

ubuntu/linux-hwe*

ubuntu/linux-hwe-5.4*

ubuntu/linux-hwe-edge*

ubuntu/linux-ibm-5.4*

ubuntu/linux-oem*

ubuntu/linux-oracle-5.0*

ubuntu/linux-oracle-5.3*

ubuntu/linux-oracle-5.4*

ubuntu/linux-raspi-5.4*

ubuntu/linux*

ubuntu/linux-aws*

ubuntu/linux-aws-5.11*

ubuntu/linux-aws-5.13*

ubuntu/linux-aws-5.15<5.15.0-1117.124~20.04.1

5.15.0-1117.124~20.04.1

ubuntu/linux-aws-5.8*

ubuntu/linux-azure*

ubuntu/linux-azure-5.11*

ubuntu/linux-azure-5.13*

ubuntu/linux-azure-5.15<5.15.0-1123.132~20.04.1

5.15.0-1123.132~20.04.1

ubuntu/linux-azure-5.8*

ubuntu/linux-azure-fde*

ubuntu/linux-azure-fde-5.15<5.15.0-1122.131~20.04.1

5.15.0-1122.131~20.04.1

ubuntu/linux-bluefield*

ubuntu/linux-gcp*

ubuntu/linux-gcp-5.11*

ubuntu/linux-gcp-5.13*

ubuntu/linux-gcp-5.15<5.15.0-1118.128~20.04.1

5.15.0-1118.128~20.04.1

ubuntu/linux-gcp-5.8*

ubuntu/linux-gke*

ubuntu/linux-gke-5.15*

ubuntu/linux-gkeop*

ubuntu/linux-gkeop-5.15*

ubuntu/linux-hwe-5.11*

ubuntu/linux-hwe-5.13*

ubuntu/linux-hwe-5.15<5.15.0-198.208~20.04.1

5.15.0-198.208~20.04.1

ubuntu/linux-hwe-5.8*

ubuntu/linux-ibm*

ubuntu/linux-ibm-5.15<5.15.0-1111.115~20.04.1

5.15.0-1111.115~20.04.1

ubuntu/linux-intel-5.13*

ubuntu/linux-intel-iotg-5.15<5.15.0-1112.118~20.04.1

5.15.0-1112.118~20.04.1

ubuntu/linux-iot*

ubuntu/linux-kvm*

ubuntu/linux-lowlatency-hwe-5.15<5.15.0-195.205~20.04.1

5.15.0-195.205~20.04.1

ubuntu/linux-nvidia-tegra-5.15*

ubuntu/linux-oem-5.10*

ubuntu/linux-oem-5.13*

ubuntu/linux-oem-5.6*

ubuntu/linux-oracle*

ubuntu/linux-oracle-5.11*

ubuntu/linux-oracle-5.13*

ubuntu/linux-oracle-5.15<5.15.0-1114.120~20.04.1

5.15.0-1114.120~20.04.1

ubuntu/linux-oracle-5.8*

ubuntu/linux-raspi*

ubuntu/linux-raspi2*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.11*

ubuntu/linux-riscv-5.15<5.15.0-1111.115~20.04.1

5.15.0-1111.115~20.04.1

ubuntu/linux-riscv-5.8*

ubuntu/linux-xilinx-zynqmp*

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux<5.15.0-198.208

5.15.0-198.208

ubuntu/linux-allwinner-5.19*

ubuntu/linux-aws<5.15.0-1117.124

5.15.0-1117.124

ubuntu/linux-aws-5.19*

ubuntu/linux-aws-6.2*

ubuntu/linux-aws-6.5*

ubuntu/linux-aws-6.8<6.8.0-1066.69~22.04.1

6.8.0-1066.69~22.04.1

ubuntu/linux-azure<5.15.0-1123.132

5.15.0-1123.132

ubuntu/linux-azure-5.19*

ubuntu/linux-azure-6.2*

ubuntu/linux-azure-6.5*

ubuntu/linux-azure-6.8<6.8.0-1070.78~22.04.1

6.8.0-1070.78~22.04.1

ubuntu/linux-azure-fde<5.15.0-1122.131

5.15.0-1122.131

ubuntu/linux-azure-fde-5.19*

ubuntu/linux-azure-fde-6.2*

ubuntu/linux-azure-fde-6.8<6.8.0-1068.75~22.04.1

6.8.0-1068.75~22.04.1

ubuntu/linux-gcp<5.15.0-1118.128

5.15.0-1118.128

ubuntu/linux-gcp-5.19*

ubuntu/linux-gcp-6.2*

ubuntu/linux-gcp-6.5*

ubuntu/linux-gcp-6.8<6.8.0-1070.78~22.04.1

6.8.0-1070.78~22.04.1

ubuntu/linux-gke<5.15.0-1113.119

5.15.0-1113.119

ubuntu/linux-gkeop<5.15.0-1100.108

5.15.0-1100.108

ubuntu/linux-hwe-5.19*

ubuntu/linux-hwe-6.2*

ubuntu/linux-hwe-6.5*

ubuntu/linux-ibm<5.15.0-1111.115

5.15.0-1111.115

ubuntu/linux-ibm-6.8<6.8.0-1066.67~22.04.1

6.8.0-1066.67~22.04.1

ubuntu/linux-intel-iot-realtime*

ubuntu/linux-intel-iotg<5.15.0-1112.118

5.15.0-1112.118

ubuntu/linux-kvm<5.15.0-1109.114

5.15.0-1109.114

ubuntu/linux-lowlatency<5.15.0-195.205

5.15.0-195.205

ubuntu/linux-lowlatency-hwe-5.19*

ubuntu/linux-lowlatency-hwe-6.2*

ubuntu/linux-lowlatency-hwe-6.5*

ubuntu/linux-lowlatency-hwe-6.8<6.8.0-146.146.1~22.04.1

6.8.0-146.146.1~22.04.1

ubuntu/linux-nvidia<5.15.0-1112.113

5.15.0-1112.113

ubuntu/linux-nvidia-6.2*

ubuntu/linux-nvidia-6.5*

ubuntu/linux-nvidia-6.8<6.8.0-1064.67~22.04.1

6.8.0-1064.67~22.04.1

ubuntu/linux-nvidia-tegra*

ubuntu/linux-nvidia-tegra-igx*

ubuntu/linux-oem-5.17*

ubuntu/linux-oem-6.0*

ubuntu/linux-oem-6.1*

ubuntu/linux-oem-6.5*

ubuntu/linux-oracle<5.15.0-1114.120

5.15.0-1114.120

ubuntu/linux-oracle-6.5*

ubuntu/linux-oracle-6.8*

ubuntu/linux-raspi*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.19*

ubuntu/linux-riscv-6.5*

ubuntu/linux-riscv-6.8<6.8.0-146.146~22.04.1

6.8.0-146.146~22.04.1

ubuntu/linux-starfive-5.19*

ubuntu/linux-starfive-6.2*

ubuntu/linux-starfive-6.5*

ubuntu/linux-xilinx-zynqmp<5.15.0-1080.84

5.15.0-1080.84

ubuntu/linux-bluefield<5.15.0-1101.103

5.15.0-1101.103

ubuntu/linux-intel-iot-realtime<5.15.0-1109.111

5.15.0-1109.111

ubuntu/linux-realtime<5.15.0-1116.125

5.15.0-1116.125

ubuntu/linux-realtime-6.8<6.8.1-1061.62~22.04.1

6.8.1-1061.62~22.04.1

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux-aws-fips<5.15.0-1117.124+fips1

5.15.0-1117.124+fips1

ubuntu/linux-azure-fips<5.15.0-1123.132+fips1

5.15.0-1123.132+fips1

ubuntu/linux-fips<5.15.0-198.208+fips1

5.15.0-198.208+fips1

ubuntu/linux-gcp-fips<5.15.0-1118.128+fips1

5.15.0-1118.128+fips1

ubuntu/linux<6.8.0-146.146

6.8.0-146.146

ubuntu/linux-aws<6.8.0-1066.69

6.8.0-1066.69

ubuntu/linux-aws-6.14*

ubuntu/linux-aws-6.17*

ubuntu/linux-azure<6.8.0-1070.78

6.8.0-1070.78

ubuntu/linux-azure-6.11*

ubuntu/linux-azure-6.14*

ubuntu/linux-azure-6.17*

ubuntu/linux-azure-7.0<7.0.0-1014.14~24.04.1

7.0.0-1014.14~24.04.1

ubuntu/linux-azure-fde<6.8.0-1068.75

6.8.0-1068.75

ubuntu/linux-azure-fde-6.14*

ubuntu/linux-azure-fde-6.17*

ubuntu/linux-azure-fde-7.0<7.0.0-1013.13~24.04.1

7.0.0-1013.13~24.04.1

ubuntu/linux-azure-nvidia*

ubuntu/linux-azure-nvidia-6.14*

ubuntu/linux-gcp<6.8.0-1070.78

6.8.0-1070.78

ubuntu/linux-gcp-6.11*

ubuntu/linux-gcp-6.14*

ubuntu/linux-gcp-7.0<7.0.0-1011.11~24.04.1

7.0.0-1011.11~24.04.1

ubuntu/linux-gke<6.8.0-1065.73

6.8.0-1065.73

ubuntu/linux-gkeop<6.8.0-1051.55

6.8.0-1051.55

ubuntu/linux-hwe-6.11*

ubuntu/linux-hwe-6.14*

ubuntu/linux-hwe-6.17*

ubuntu/linux-hwe-7.0<7.0.0-28.28~24.04.1

7.0.0-28.28~24.04.1

ubuntu/linux-ibm<6.8.0-1066.67

6.8.0-1066.67

ubuntu/linux-lowlatency<6.8.0-146.146.1

6.8.0-146.146.1

ubuntu/linux-lowlatency-hwe-6.11*

ubuntu/linux-nvidia<6.8.0-1064.67

6.8.0-1064.67

ubuntu/linux-nvidia-6.11*

ubuntu/linux-nvidia-6.17*

ubuntu/linux-nvidia-7.0<7.0.0-1016.16~24.04.1

7.0.0-1016.16~24.04.1

ubuntu/linux-nvidia-lowlatency<6.8.0-1064.67.1

6.8.0-1064.67.1

ubuntu/linux-nvidia-tegra*

ubuntu/linux-oem-6.11*

ubuntu/linux-oem-6.14*

ubuntu/linux-oem-6.17*

ubuntu/linux-oem-6.8*

ubuntu/linux-oracle<6.8.0-1063.66

6.8.0-1063.66

ubuntu/linux-oracle-6.14*

ubuntu/linux-oracle-6.17*

ubuntu/linux-oracle-7.0<7.0.0-1011.11~24.04.1

7.0.0-1011.11~24.04.1

ubuntu/linux-raspi*

ubuntu/linux-raspi-realtime*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-6.14*

ubuntu/linux-riscv-6.17*

ubuntu/linux-riscv-7.0<7.0.0-28.28.1~24.04.3

7.0.0-28.28.1~24.04.3

ubuntu/linux-xilinx*

ubuntu/linux-bluefield<6.8.0-1032.37

6.8.0-1032.37

ubuntu/linux-raspi-realtime*

ubuntu/linux-realtime<6.8.1-1061.62

6.8.1-1061.62

ubuntu/linux-realtime-6.14*

ubuntu/linux-realtime-6.17*

ubuntu/linux-aws-fips<6.8.0-1066.69+fips1

6.8.0-1066.69+fips1

ubuntu/linux-azure-fips<6.8.0-1069.77+fips1

6.8.0-1069.77+fips1

ubuntu/linux-fips<6.8.0-146.146+fips1

6.8.0-146.146+fips1

ubuntu/linux-gcp-fips<6.8.0-1070.78+fips1

6.8.0-1070.78+fips1

ubuntu/linux*

ubuntu/linux-aws*

ubuntu/linux-azure*

ubuntu/linux-azure-fde*

ubuntu/linux-gcp*

ubuntu/linux-oracle*

ubuntu/linux-raspi*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux<7.0.0-28.28

7.0.0-28.28

ubuntu/linux-aws<7.0.0-1009.9

7.0.0-1009.9

ubuntu/linux-azure<7.0.0-1010.10

7.0.0-1010.10

ubuntu/linux-azure-fde<7.0.0-1009.9

7.0.0-1009.9

ubuntu/linux-gcp<7.0.0-1008.8

7.0.0-1008.8

ubuntu/linux-gke<7.0.0-1003.4

7.0.0-1003.4

ubuntu/linux-ibm<7.0.0-1010.10

7.0.0-1010.10

ubuntu/linux-nvidia<7.0.0-1016.16

7.0.0-1016.16

ubuntu/linux-nvidia-bos<7.0.0-2016.16

7.0.0-2016.16

ubuntu/linux-oem-7.0<7.0.0-1009.9

7.0.0-1009.9

ubuntu/linux-oracle<7.0.0-1008.8

7.0.0-1008.8

ubuntu/linux-raspi<7.0.0-1015.15

7.0.0-1015.15

ubuntu/linux-realtime<7.0.0-28.28.1

7.0.0-28.28.1

ubuntu/linux-riscv<7.0.0-28.28.1

7.0.0-28.28.1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade ubuntu/linux-aws-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1117.124~20.04.1
Upgrade
Upgrade ubuntu/linux-azure-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1123.132~20.04.1
Upgrade
Upgrade ubuntu/linux-azure-fde-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1122.131~20.04.1
Upgrade
Upgrade ubuntu/linux-gcp-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1118.128~20.04.1
Upgrade
Upgrade ubuntu/linux-hwe-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-198.208~20.04.1
Upgrade
Upgrade ubuntu/linux-ibm-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1111.115~20.04.1
Upgrade
Upgrade ubuntu/linux-intel-iotg-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1112.118~20.04.1
Upgrade
Upgrade ubuntu/linux-lowlatency-hwe-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-195.205~20.04.1
Upgrade
Upgrade ubuntu/linux-oracle-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1114.120~20.04.1
Upgrade
Upgrade ubuntu/linux-riscv-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1111.115~20.04.1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 5.15.0-198.208
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 5.15.0-1117.124
Upgrade
Upgrade ubuntu/linux-aws-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1066.69~22.04.1
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 5.15.0-1123.132
Upgrade
Upgrade ubuntu/linux-azure-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1070.78~22.04.1
Upgrade
Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.
Fixed in 5.15.0-1122.131
Upgrade
Upgrade ubuntu/linux-azure-fde-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1068.75~22.04.1
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 5.15.0-1118.128
Upgrade
Upgrade ubuntu/linux-gcp-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1070.78~22.04.1
Upgrade
Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.
Fixed in 5.15.0-1113.119
Upgrade
Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.
Fixed in 5.15.0-1100.108
Upgrade
Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.
Fixed in 5.15.0-1111.115
Upgrade
Upgrade ubuntu/linux-ibm-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1066.67~22.04.1
Upgrade
Upgrade ubuntu/linux-intel-iotg to a version that resolves this vulnerability.
Fixed in 5.15.0-1112.118
Upgrade
Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.
Fixed in 5.15.0-1109.114
Upgrade
Upgrade ubuntu/linux-lowlatency to a version that resolves this vulnerability.
Fixed in 5.15.0-195.205
Upgrade
Upgrade ubuntu/linux-lowlatency-hwe-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-146.146.1~22.04.1
Upgrade
Upgrade ubuntu/linux-nvidia to a version that resolves this vulnerability.
Fixed in 5.15.0-1112.113
Upgrade
Upgrade ubuntu/linux-nvidia-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1064.67~22.04.1
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 5.15.0-1114.120
Upgrade
Upgrade ubuntu/linux-riscv-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-146.146~22.04.1
Upgrade
Upgrade ubuntu/linux-xilinx-zynqmp to a version that resolves this vulnerability.
Fixed in 5.15.0-1080.84
Upgrade
Upgrade ubuntu/linux-bluefield to a version that resolves this vulnerability.
Fixed in 5.15.0-1101.103
Upgrade
Upgrade ubuntu/linux-intel-iot-realtime to a version that resolves this vulnerability.
Fixed in 5.15.0-1109.111
Upgrade
Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.
Fixed in 5.15.0-1116.125
Upgrade
Upgrade ubuntu/linux-realtime-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.1-1061.62~22.04.1
Upgrade
Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-1117.124+fips1
Upgrade
Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-1123.132+fips1
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Fixed in 5.15.0-198.208+fips1
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Fixed in 5.15.0-1118.128+fips1
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Fixed in 6.8.0-146.146
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Fixed in 6.8.0-1066.69
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Fixed in 6.8.0-1070.78
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Fixed in 7.0.0-1014.14~24.04.1
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Fixed in 6.8.0-1068.75
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Fixed in 7.0.0-1013.13~24.04.1
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Fixed in 6.8.0-1070.78
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Fixed in 7.0.0-1011.11~24.04.1
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Fixed in 6.8.0-1065.73
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Fixed in 6.8.0-1051.55
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Fixed in 7.0.0-28.28~24.04.1
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Fixed in 6.8.0-1066.67
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Fixed in 6.8.0-1064.67
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Fixed in 6.8.0-1064.67.1
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Fixed in 6.8.0-1063.66
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Fixed in 7.0.0-1011.11~24.04.1
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Fixed in 6.8.0-1032.37
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Fixed in 6.8.1-1061.62
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Fixed in 7.0.0-1010.10
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Fixed in 7.0.0-1003.4
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Fixed in 7.0.0-1016.16
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Fixed in 7.0.0-2016.16
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Fixed in 7.0.0-1009.9
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Fixed in 7.0.0-1008.8
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Fixed in 7.0.0-1015.15
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Fixed in 7.0.0-28.28.1
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Fixed in 7.0.0-28.28.1
Compensating control
Skip "old-style" classification on shared blocks to prevent invalid cls_fw filters from classifying packets before validation destroys them, avoiding the NULL dereference of the filter's old entry.

Event History

Jun 24, 2026

CVE Published

via OSV·05:17 PM

Data Sourced

via OSV·05:17 PM

DescriptionSeverityAffected Software

Frequently Asked Questions

Who is realistically exposed to this issue?

Systems running one of the listed Ubuntu kernel packages are in scope when traffic control filters using the cls_fw classifier are configured. The demonstrated condition involves a shared TC block, a matchall filter with an skbedit action, and adding an fw filter while traffic is being processed.

What level of access does an attacker need?

The supplied CVSS vector indicates local access, low privileges, no user interaction, and that an additional attack requirement must be present. The reproducer uses network and traffic-control commands to create interfaces, configure qdiscs and filters, and generate traffic.

What is the impact if the issue is triggered?

The described behavior can cause fw_classify() to hit a kernel WARN_ON due to a NULL dereference involving an old filter. The CVSS vector rates availability impact as high, while confidentiality and integrity impacts are listed as none.

How can I determine whether my configuration is exposed?

Review TC configuration for shared blocks that use the fw classifier, particularly where filters are added or changed while packets can traverse the block. The report specifically identifies a race in which an invalid filter may be published to the datapath before its change validation completes.

UBUNTU-CVE-2026-53080: Medium severity ubuntu/linux-hwe-edge vulnerability

Affected Software

Remediation

Event History

Frequently Asked Questions

Who is realistically exposed to this issue?

What level of access does an attacker need?

What is the impact if the issue is triggered?

How can I determine whether my configuration is exposed?

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