UBUNTU-CVE-2026-23428: Use After Free

Q: Which systems are exposed to this issue?

Systems running one of the listed Ubuntu Linux kernel packages may be exposed when the ksmbd SMB server is in use. The affected package list includes linux, linux-realtime, linux-azure, linux-gcp, linux-azure-fde, linux-riscv, linux-gke, and linux-gkeop.

Q: What does an attacker need to trigger the flaw?

An attacker needs SMB access to a ksmbd server and must send a compound SMB request that first disconnects a tree connection and then issues a subsequent command using the reused connection. The vulnerability is reachable over the network and requires low privileges according to the supplied severity vector.

Q: What happens when the issue is triggered?

A tree-disconnect command can mark the connection disconnected and free its share configuration, while a later command in the same compound request dereferences that freed configuration. This causes a kernel use-after-free; the supplied report shows it occurring during an SMB write operation.

Published Apr 3, 2026

Updated

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free of shareconf in compound request smb2getksmbdtcon() reuses work->tcon in compound requests without validating tcon->tstate. ksmbdtreeconnlookup() checks tstate == TREECONNECTED on the initial lookup path, but the compound reuse path bypasses this check entirely. If a prior command in the compound (SMB2TREEDISCONNECT) sets tstate to TREEDISCONNECTED and frees shareconf via ksmbdshareconfigput(), subsequent commands dereference the freed shareconf through work->tcon->shareconf. KASAN report: [ 4.144653] ================================================================== [ 4.145059] BUG: KASAN: slab-use-after-free in smb2write+0xc74/0xe70 [ 4.145415] Read of size 4 at addr ffff88810430c194 by task kworker/1:1/44 [ 4.145772] [ 4.145867] CPU: 1 UID: 0 PID: 44 Comm: kworker/1:1 Not tainted 7.0.0-rc3+ #60 PREEMPTLAZY [ 4.145871] Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, archcaps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 4.145875] Workqueue: ksmbd-io handleksmbdwork [ 4.145888] Call Trace: [ 4.145892] <TASK> [ 4.145894] dumpstacklvl+0x64/0x80 [ 4.145910] printreport+0xce/0x660 [ 4.145919] ? pfxrawspinlockirqsave+0x10/0x10 [ 4.145928] ? smb2write+0xc74/0xe70 [ 4.145931] kasanreport+0xce/0x100 [ 4.145934] ? smb2write+0xc74/0xe70 [ 4.145937] smb2write+0xc74/0xe70 [ 4.145939] ? pfxsmb2write+0x10/0x10 [ 4.145942] ? rawspinunlock+0xe/0x30 [ 4.145945] ? ksmbdsmb2checkmessage+0xeb2/0x24c0 [ 4.145948] ? smb2treedisconnect+0x31c/0x480 [ 4.145951] handleksmbdwork+0x40f/0x1080 [ 4.145953] processonework+0x5fa/0xef0 [ 4.145962] ? assignwork+0x122/0x3e0 [ 4.145964] workerthread+0x54b/0xf70 [ 4.145967] ? pfxworkerthread+0x10/0x10 [ 4.145970] kthread+0x346/0x470 [ 4.145976] ? recalcsigpending+0x19b/0x230 [ 4.145980] ? pfxkthread+0x10/0x10 [ 4.145984] retfromfork+0x4fb/0x6c0 [ 4.145992] ? pfxretfromfork+0x10/0x10 [ 4.145995] ? switchto+0x36c/0xbe0 [ 4.145999] ? pfxkthread+0x10/0x10 [ 4.146003] retfromforkasm+0x1a/0x30 [ 4.146013] </TASK> [ 4.146014] [ 4.149858] Allocated by task 44: [ 4.149953] kasansavestack+0x33/0x60 [ 4.150061] kasansavetrack+0x14/0x30 [ 4.150169] kasankmalloc+0x8f/0xa0 [ 4.150274] ksmbdshareconfigget+0x1dd/0xdd0 [ 4.150401] ksmbdtreeconnconnect+0x7e/0x600 [ 4.150529] smb2treeconnect+0x2e6/0x1000 [ 4.150645] handleksmbdwork+0x40f/0x1080 [ 4.150761] processonework+0x5fa/0xef0 [ 4.150873] workerthread+0x54b/0xf70 [ 4.150978] kthread+0x346/0x470 [ 4.151071] retfromfork+0x4fb/0x6c0 [ 4.151176] retfromforkasm+0x1a/0x30 [ 4.151286] [ 4.151332] Freed by task 44: [ 4.151418] kasansavestack+0x33/0x60 [ 4.151526] kasansavetrack+0x14/0x30 [ 4.151634] kasansavefreeinfo+0x3b/0x60 [ 4.151751] kasanslabfree+0x43/0x70 [ 4.151861] kfree+0x1ca/0x430 [ 4.151952] ksmbdtreeconndisconnect+0xc8/0x190 [ 4.152088] smb2treedisconnect+0x1cd/0x480 [ 4.152211] handleksmbdwork+0x40f/0x1080 [ 4.152326] processonework+0x5fa/0xef0 [ 4.152438] workerthread+0x54b/0xf70 [ 4.152545] kthread+0x346/0x470 [ 4.152638] retfromfork+0x4fb/0x6c0 [ 4.152743] retfromforkasm+0x1a/0x30 [ 4.152853] [ 4.152900] The buggy address belongs to the object at ffff88810430c180 [ 4.152900] which belongs to the cache kmalloc-96 of size 96 [ 4.153226] The buggy address is located 20 bytes inside of [ 4.153226] freed 96-byte region [ffff88810430c180, ffff88810430c1e0) [ 4.153549] [ 4.153596] The buggy address belongs to the physical page: [ 4.153750] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88810430ce80 pfn:0x10430c [ 4.154000] flags: 0x ---truncated---

Affected Software

189 affected componentsFixes available

ubuntu/linux-hwe-edge*

ubuntu/linux-aws-5.0*

ubuntu/linux-aws-5.3*

ubuntu/linux-azure*

ubuntu/linux-azure-5.3*

ubuntu/linux-azure-edge*

ubuntu/linux-gcp*

ubuntu/linux-gcp-5.3*

ubuntu/linux-gke-4.15*

ubuntu/linux-gke-5.4*

ubuntu/linux-gkeop-5.4*

ubuntu/linux-hwe*

ubuntu/linux-hwe-edge*

ubuntu/linux-oem*

ubuntu/linux-oracle-5.0*

ubuntu/linux-oracle-5.3*

ubuntu/linux-aws-5.11*

ubuntu/linux-aws-5.13*

ubuntu/linux-aws-5.15<5.15.0-1111.118~20.04.1

5.15.0-1111.118~20.04.1

ubuntu/linux-aws-5.8*

ubuntu/linux-azure-5.11*

ubuntu/linux-azure-5.13*

ubuntu/linux-azure-5.15<5.15.0-1116.125~20.04.1

5.15.0-1116.125~20.04.1

ubuntu/linux-azure-5.8*

ubuntu/linux-azure-fde*

ubuntu/linux-azure-fde-5.15<5.15.0-1116.125~20.04.1

5.15.0-1116.125~20.04.1

ubuntu/linux-gcp-5.11*

ubuntu/linux-gcp-5.13*

ubuntu/linux-gcp-5.15<5.15.0-1111.121~20.04.1

5.15.0-1111.121~20.04.1

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<5.15.0-185.195~20.04.1

5.15.0-185.195~20.04.1

ubuntu/linux-hwe-5.8*

ubuntu/linux-ibm-5.15<5.15.0-1105.109~20.04.1

5.15.0-1105.109~20.04.1

ubuntu/linux-intel-5.13*

ubuntu/linux-intel-iotg-5.15<5.15.0-1106.112~20.04.1

5.15.0-1106.112~20.04.1

ubuntu/linux-lowlatency-hwe-5.15<5.15.0-183.193~20.04.1

5.15.0-183.193~20.04.1

ubuntu/linux-nvidia-tegra-5.15<5.15.0-1063.63~20.04.1

5.15.0-1063.63~20.04.1

ubuntu/linux-oem-5.10*

ubuntu/linux-oem-5.13*

ubuntu/linux-oem-5.6*

ubuntu/linux-oracle-5.11*

ubuntu/linux-oracle-5.13*

ubuntu/linux-oracle-5.15<5.15.0-1108.114~20.04.1

5.15.0-1108.114~20.04.1

ubuntu/linux-oracle-5.8*

ubuntu/linux-raspi2*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.11*

ubuntu/linux-riscv-5.15<5.15.0-1105.109~20.04.1

5.15.0-1105.109~20.04.1

ubuntu/linux-riscv-5.8*

ubuntu/linux<5.15.0-185.195

5.15.0-185.195

ubuntu/linux-allwinner-5.19*

ubuntu/linux-aws<5.15.0-1111.118

5.15.0-1111.118

ubuntu/linux-aws-5.19*

ubuntu/linux-aws-6.2*

ubuntu/linux-aws-6.5*

ubuntu/linux-aws-6.8<6.8.0-1060.63~22.04.1

6.8.0-1060.63~22.04.1

ubuntu/linux-azure<5.15.0-1116.125

5.15.0-1116.125

ubuntu/linux-azure-5.19*

ubuntu/linux-azure-6.2*

ubuntu/linux-azure-6.5*

ubuntu/linux-azure-6.8<6.8.0-1063.71~22.04.1

6.8.0-1063.71~22.04.1

ubuntu/linux-azure-fde<5.15.0-1116.125

5.15.0-1116.125

ubuntu/linux-azure-fde-5.19*

ubuntu/linux-azure-fde-6.2*

ubuntu/linux-azure-fde-6.8<6.8.0-1062.69~22.04.1

6.8.0-1062.69~22.04.1

ubuntu/linux-gcp<5.15.0-1111.121

5.15.0-1111.121

ubuntu/linux-gcp-5.19*

ubuntu/linux-gcp-6.2*

ubuntu/linux-gcp-6.5*

ubuntu/linux-gcp-6.8<6.8.0-1063.69~22.04.1

6.8.0-1063.69~22.04.1

ubuntu/linux-gke<5.15.0-1107.113

5.15.0-1107.113

ubuntu/linux-gkeop<5.15.0-1094.102

5.15.0-1094.102

ubuntu/linux-hwe-5.19*

ubuntu/linux-hwe-6.2*

ubuntu/linux-hwe-6.5*

ubuntu/linux-hwe-6.8<6.8.0-136.136~22.04.1

6.8.0-136.136~22.04.1

ubuntu/linux-ibm<5.15.0-1105.109

5.15.0-1105.109

ubuntu/linux-ibm-6.8<6.8.0-1060.61~22.04.1

6.8.0-1060.61~22.04.1

ubuntu/linux-intel-iot-realtime*

ubuntu/linux-intel-iotg<5.15.0-1106.112

5.15.0-1106.112

ubuntu/linux-kvm<5.15.0-1103.108

5.15.0-1103.108

ubuntu/linux-lowlatency<5.15.0-183.193

5.15.0-183.193

ubuntu/linux-lowlatency-hwe-5.19*

ubuntu/linux-lowlatency-hwe-6.2*

ubuntu/linux-lowlatency-hwe-6.5*

ubuntu/linux-lowlatency-hwe-6.8<6.8.0-134.134.1~22.04.1

6.8.0-134.134.1~22.04.1

ubuntu/linux-nvidia<5.15.0-1106.107

5.15.0-1106.107

ubuntu/linux-nvidia-6.2*

ubuntu/linux-nvidia-6.5*

ubuntu/linux-nvidia-6.8<6.8.0-1058.61~22.04.1

6.8.0-1058.61~22.04.1

ubuntu/linux-nvidia-tegra<5.15.0-1063.63

5.15.0-1063.63

ubuntu/linux-nvidia-tegra-igx<5.15.0-1052.52

5.15.0-1052.52

ubuntu/linux-oem-5.17*

ubuntu/linux-oem-6.0*

ubuntu/linux-oem-6.1*

ubuntu/linux-oem-6.5*

ubuntu/linux-oracle<5.15.0-1108.114

5.15.0-1108.114

ubuntu/linux-oracle-6.5*

ubuntu/linux-oracle-6.8<6.8.0-1057.58~22.04.1

6.8.0-1057.58~22.04.1

ubuntu/linux-raspi<5.15.0-1105.108

5.15.0-1105.108

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.19*

ubuntu/linux-riscv-6.5*

ubuntu/linux-riscv-6.8<6.8.0-134.134~22.04.1

6.8.0-134.134~22.04.1

ubuntu/linux-starfive-5.19*

ubuntu/linux-starfive-6.2*

ubuntu/linux-starfive-6.5*

ubuntu/linux-xilinx-zynqmp<5.15.0-1074.78

5.15.0-1074.78

ubuntu/linux-bluefield<5.15.0-1095.97

5.15.0-1095.97

ubuntu/linux-intel-iot-realtime<5.15.0-1103.105

5.15.0-1103.105

ubuntu/linux-realtime<5.15.0-1110.119

5.15.0-1110.119

ubuntu/linux-realtime-6.8<6.8.1-1055.56~22.04.1

6.8.1-1055.56~22.04.1

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux-aws-fips<5.15.0-1111.118+fips1

5.15.0-1111.118+fips1

ubuntu/linux-azure-fips<5.15.0-1116.125+fips1

5.15.0-1116.125+fips1

ubuntu/linux-fips<5.15.0-185.195+fips1

5.15.0-185.195+fips1

ubuntu/linux-gcp-fips<5.15.0-1111.121+fips1

5.15.0-1111.121+fips1

ubuntu/linux<6.8.0-134.134

6.8.0-134.134

ubuntu/linux-aws<6.8.0-1060.63

6.8.0-1060.63

ubuntu/linux-aws-6.14*

ubuntu/linux-aws-6.17<6.17.0-1019.19~24.04.1

6.17.0-1019.19~24.04.1

ubuntu/linux-azure<6.8.0-1063.71

6.8.0-1063.71

ubuntu/linux-azure-6.11*

ubuntu/linux-azure-6.14*

ubuntu/linux-azure-6.17<6.17.0-1021.21~24.04.1

6.17.0-1021.21~24.04.1

ubuntu/linux-azure-fde<6.8.0-1062.69

6.8.0-1062.69

ubuntu/linux-azure-fde-6.14*

ubuntu/linux-azure-nvidia*

ubuntu/linux-azure-nvidia-6.14*

ubuntu/linux-gcp<6.8.0-1063.69

6.8.0-1063.69

ubuntu/linux-gcp-6.11*

ubuntu/linux-gcp-6.14*

ubuntu/linux-gcp-6.17<6.17.0-1020.22~24.04.1

6.17.0-1020.22~24.04.1

ubuntu/linux-gke<6.8.0-1058.64

6.8.0-1058.64

ubuntu/linux-gkeop<6.8.0-1045.48

6.8.0-1045.48

ubuntu/linux-hwe-6.11*

ubuntu/linux-hwe-6.14*

ubuntu/linux-hwe-6.17<6.17.0-40.40~24.04.1

6.17.0-40.40~24.04.1

ubuntu/linux-ibm<6.8.0-1060.61

6.8.0-1060.61

ubuntu/linux-lowlatency<6.8.0-134.134.1

6.8.0-134.134.1

ubuntu/linux-lowlatency-hwe-6.11*

ubuntu/linux-nvidia<6.8.0-1058.61

6.8.0-1058.61

ubuntu/linux-nvidia-6.11*

ubuntu/linux-nvidia-6.17<6.17.0-1026.26

6.17.0-1026.26

ubuntu/linux-nvidia-lowlatency<6.8.0-1058.61.1

6.8.0-1058.61.1

ubuntu/linux-nvidia-tegra<6.8.0-1029.30

6.8.0-1029.30

ubuntu/linux-oem-6.11*

ubuntu/linux-oem-6.14*

ubuntu/linux-oem-6.17<6.17.0-1028.28

6.17.0-1028.28

ubuntu/linux-oem-6.8*

ubuntu/linux-oracle<6.8.0-1057.58

6.8.0-1057.58

ubuntu/linux-oracle-6.14*

ubuntu/linux-oracle-6.17<6.17.0-1018.18~24.04.1

6.17.0-1018.18~24.04.1

ubuntu/linux-raspi<6.8.0-1060.64

6.8.0-1060.64

ubuntu/linux-raspi-realtime*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-6.14*

ubuntu/linux-riscv-6.17*

ubuntu/linux-vmware<6.8.0-1008.8

6.8.0-1008.8

ubuntu/linux-xilinx<6.8.0-1032.33

6.8.0-1032.33

ubuntu/linux-bluefield<6.8.0-1026.30

6.8.0-1026.30

ubuntu/linux-raspi-realtime<6.8.0-2049.50

6.8.0-2049.50

ubuntu/linux-realtime<6.8.1-1055.56

6.8.1-1055.56

ubuntu/linux-realtime-6.14*

ubuntu/linux-realtime-6.17<6.17.0-1017.19~24.04.1

6.17.0-1017.19~24.04.1

ubuntu/linux-aws-fips<6.8.0-1060.63+fips1

6.8.0-1060.63+fips1

ubuntu/linux-azure-fips<6.8.0-1062.69+fips1

6.8.0-1062.69+fips1

ubuntu/linux-fips<6.8.0-134.134+fips1

6.8.0-134.134+fips1

ubuntu/linux-gcp-fips<6.8.0-1063.69+fips1

6.8.0-1063.69+fips1

ubuntu/linux<6.17.0-40.40

6.17.0-40.40

ubuntu/linux-aws<6.17.0-1019.19

6.17.0-1019.19

ubuntu/linux-azure*

ubuntu/linux-azure-fde*

ubuntu/linux-gcp<6.17.0-1020.22

6.17.0-1020.22

ubuntu/linux-oracle<6.17.0-1018.18

6.17.0-1018.18

ubuntu/linux-raspi<6.17.0-1021.21

6.17.0-1021.21

ubuntu/linux-realtime<6.17.0-1017.19

6.17.0-1017.19

ubuntu/linux-riscv<6.17.0-40.40.1

6.17.0-40.40.1

ubuntu/linux-vmware*

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 5.15.0-1111.118~20.04.1
Upgrade
Upgrade ubuntu/linux-azure-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1116.125~20.04.1
Upgrade
Upgrade ubuntu/linux-azure-fde-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1116.125~20.04.1
Upgrade
Upgrade ubuntu/linux-gcp-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1111.121~20.04.1
Upgrade
Upgrade ubuntu/linux-hwe-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-185.195~20.04.1
Upgrade
Upgrade ubuntu/linux-ibm-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1105.109~20.04.1
Upgrade
Upgrade ubuntu/linux-intel-iotg-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1106.112~20.04.1
Upgrade
Upgrade ubuntu/linux-lowlatency-hwe-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-183.193~20.04.1
Upgrade
Upgrade ubuntu/linux-nvidia-tegra-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1063.63~20.04.1
Upgrade
Upgrade ubuntu/linux-oracle-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1108.114~20.04.1
Upgrade
Upgrade ubuntu/linux-riscv-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1105.109~20.04.1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 5.15.0-185.195
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 5.15.0-1111.118
Upgrade
Upgrade ubuntu/linux-aws-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1060.63~22.04.1
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 5.15.0-1116.125
Upgrade
Upgrade ubuntu/linux-azure-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1063.71~22.04.1
Upgrade
Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.
Fixed in 5.15.0-1116.125
Upgrade
Upgrade ubuntu/linux-azure-fde-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1062.69~22.04.1
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 5.15.0-1111.121
Upgrade
Upgrade ubuntu/linux-gcp-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1063.69~22.04.1
Upgrade
Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.
Fixed in 5.15.0-1107.113
Upgrade
Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.
Fixed in 5.15.0-1094.102
Upgrade
Upgrade ubuntu/linux-hwe-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-136.136~22.04.1
Upgrade
Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.
Fixed in 5.15.0-1105.109
Upgrade
Upgrade ubuntu/linux-ibm-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1060.61~22.04.1
Upgrade
Upgrade ubuntu/linux-intel-iotg to a version that resolves this vulnerability.
Fixed in 5.15.0-1106.112
Upgrade
Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.
Fixed in 5.15.0-1103.108
Upgrade
Upgrade ubuntu/linux-lowlatency to a version that resolves this vulnerability.
Fixed in 5.15.0-183.193
Upgrade
Upgrade ubuntu/linux-lowlatency-hwe-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-134.134.1~22.04.1
Upgrade
Upgrade ubuntu/linux-nvidia to a version that resolves this vulnerability.
Fixed in 5.15.0-1106.107
Upgrade
Upgrade ubuntu/linux-nvidia-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1058.61~22.04.1
Upgrade
Upgrade ubuntu/linux-nvidia-tegra to a version that resolves this vulnerability.
Fixed in 5.15.0-1063.63
Upgrade
Upgrade ubuntu/linux-nvidia-tegra-igx to a version that resolves this vulnerability.
Fixed in 5.15.0-1052.52
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 5.15.0-1108.114
Upgrade
Upgrade ubuntu/linux-oracle-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1057.58~22.04.1
Upgrade
Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.
Fixed in 5.15.0-1105.108
Upgrade
Upgrade ubuntu/linux-riscv-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-134.134~22.04.1
Upgrade
Upgrade ubuntu/linux-xilinx-zynqmp to a version that resolves this vulnerability.
Fixed in 5.15.0-1074.78
Upgrade
Upgrade ubuntu/linux-bluefield to a version that resolves this vulnerability.
Fixed in 5.15.0-1095.97
Upgrade
Upgrade ubuntu/linux-intel-iot-realtime to a version that resolves this vulnerability.
Fixed in 5.15.0-1103.105
Upgrade
Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.
Fixed in 5.15.0-1110.119
Upgrade
Upgrade ubuntu/linux-realtime-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.1-1055.56~22.04.1
Upgrade
Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-1111.118+fips1
Upgrade
Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-1116.125+fips1
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Fixed in 5.15.0-185.195+fips1
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Fixed in 5.15.0-1111.121+fips1
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Fixed in 6.8.0-134.134
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Fixed in 6.8.0-1060.63
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Fixed in 6.17.0-1019.19~24.04.1
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Fixed in 6.8.0-1063.71
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Fixed in 6.17.0-1021.21~24.04.1
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Fixed in 6.8.0-1062.69
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Fixed in 6.8.0-1063.69
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Fixed in 6.17.0-1020.22~24.04.1
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Fixed in 6.8.0-1058.64
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Fixed in 6.8.0-1045.48
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Fixed in 6.17.0-40.40~24.04.1
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Fixed in 6.8.0-1060.61
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Fixed in 6.8.0-134.134.1
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Fixed in 6.8.0-1058.61
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Fixed in 6.17.0-1026.26
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Fixed in 6.8.0-1058.61.1
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Fixed in 6.8.0-1029.30
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Fixed in 6.17.0-1028.28
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Fixed in 6.8.0-1057.58
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Fixed in 6.17.0-1018.18~24.04.1
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Fixed in 6.8.0-1060.64
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Fixed in 6.8.0-1008.8
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Fixed in 6.8.0-1032.33
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Fixed in 6.8.0-1026.30
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Fixed in 6.8.0-2049.50
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Fixed in 6.8.1-1055.56
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Fixed in 6.17.0-1017.19~24.04.1
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Fixed in 6.8.0-1060.63+fips1
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Fixed in 6.8.0-1062.69+fips1
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Fixed in 6.8.0-134.134+fips1
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Fixed in 6.8.0-1063.69+fips1
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Fixed in 6.17.0-40.40
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Fixed in 6.17.0-1019.19
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Fixed in 6.17.0-1020.22
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Fixed in 6.17.0-1018.18
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Fixed in 6.17.0-1021.21
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Fixed in 6.17.0-1017.19
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Fixed in 6.17.0-40.40.1

Event History

Apr 3, 2026

CVE Published

via OSV·04:16 PM

Data Sourced

via OSV·04:16 PM

DescriptionSeverityAffected Software

Frequently Asked Questions

Which systems are exposed to this issue?

Systems running one of the listed Ubuntu Linux kernel packages may be exposed when the ksmbd SMB server is in use. The affected package list includes linux, linux-realtime, linux-azure, linux-gcp, linux-azure-fde, linux-riscv, linux-gke, and linux-gkeop.

What does an attacker need to trigger the flaw?

An attacker needs SMB access to a ksmbd server and must send a compound SMB request that first disconnects a tree connection and then issues a subsequent command using the reused connection. The vulnerability is reachable over the network and requires low privileges according to the supplied severity vector.

What happens when the issue is triggered?

A tree-disconnect command can mark the connection disconnected and free its share configuration, while a later command in the same compound request dereferences that freed configuration. This causes a kernel use-after-free; the supplied report shows it occurring during an SMB write operation.

UBUNTU-CVE-2026-23428: Use After Free

Affected Software

Remediation

Event History

Frequently Asked Questions

Which systems are exposed to this issue?

What does an attacker need to trigger the flaw?

What happens when the issue is triggered?

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