CVE-2026-89784: SUNRPC: check rpc_sockaddr2uaddr() return value in rpcb_register_inet4/6

Q: What conditions are required to trigger the kernel crash?

The failure requires rpc_sockaddr2uaddr() to return NULL because its final kstrdup() allocation fails while rpcb_register_inet4() or rpcb_register_inet6() is registering with RPCBPROC_SET. The unchecked NULL then reaches encode_rpcb_string(), which calls strlen() on it and oopses the kernel.

Q: Is this issue remotely exploitable based on the available information?

The provided information describes an allocation-failure path during local kernel SUNRPC processing and demonstrates reproduction with failslab. It does not establish a remote trigger or identify an attacker-controlled input that can force the allocation failure.

Q: How can I determine whether a system has encountered this issue?

Look for a kernel oops with strlen in the call trace, followed by encode_rpcb_string, rpcb_enc_getaddr, rpc_call_sync, and RPC bind registration functions. With KASAN, the report may appear as a general protection fault involving the shadow of address zero.

Q: What is the immediate mitigation if an updated kernel cannot be deployed?

The supplied data does not provide a configuration workaround. The described trigger depends on a memory-allocation failure during SUNRPC RPC bind registration, so avoid relying on unverified mitigations and plan to deploy a kernel containing the referenced fix.

Published Sep 16, 2026

Updated

In the Linux kernel, the following vulnerability has been resolved:

SUNRPC: check rpcsockaddr2uaddr() return value in rpcbregisterinet4/6

rpcbregisterinet4() and rpcbregisterinet6() store the result of rpcsockaddr2uaddr() into map->raddr without checking it for NULL. rpcsockaddr2uaddr() returns NULL when its final kstrdup() fails, and the unchecked NULL is then carried into the synchronous RPCBPROCSET encode path: rpcbregistercall() -> rpccallsync() -> rpcbencgetaddr() -> encoderpcbstring(), whose first statement is strlen(string), dereferencing NULL and oopsing the kernel.

The crash reproduces under failslab on v6.12; with KASAN the NULL dereference surfaces as a fault on the shadow of address zero:

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000 [#1] PREEMPT SMP KASAN RIP: 0010:strlen (lib/string.c:409) Call Trace: encoderpcbstring (net/sunrpc/rpcbclnt.c:890) rpcbencgetaddr (net/sunrpc/rpcbclnt.c:910) rpcauthwrapreqencode (net/sunrpc/auth.c:745) callencode (net/sunrpc/clnt.c:1966) rpcexecute (net/sunrpc/sched.c:952) rpcruntask (net/sunrpc/clnt.c:1243) rpccallsync (net/sunrpc/clnt.c:1272) rpcbv4register (net/sunrpc/rpcbclnt.c:500) svcgenericrpcbindset nfsdrpcbindset svcregister svcsetupsocket svcaddsock writeports nfsctltransactionwrite vfswrite

The crash is reachable when an in-kernel RPC service (nfsd, lockd, nfs-callback) registers with the local rpcbind under enough memory pressure for the small GFPKERNEL kstrdup() in rpcsockaddr2uaddr() to fail. The asynchronous getport path already handles this exact failure mode by returning -ENOMEM; only the two register helpers omit the check.

Mirror that handling: bail out with -ENOMEM when rpcsockaddr2uaddr() returns NULL, before the address is fed into the encoder.

Affected Software

259 affected componentsFixes available

Linux Kernel>

Microsoft azl3 kernel 6.6.152.1-1<6.6.157.1-1

6.6.157.1-1

debian/linux<=6.1.176-1, <=6.12.107-1

6.1.190-16.12.116-17.2.15-17.3.3-1

debian/linux-6.12

6.12.115-2~deb12u1

ubuntu/linux*

ubuntu/linux-aws*

ubuntu/linux-azure*

ubuntu/linux-lts-xenial*

ubuntu/linux*

ubuntu/linux-aws*

ubuntu/linux-aws-hwe*

ubuntu/linux-azure*

ubuntu/linux-gcp*

ubuntu/linux-hwe*

ubuntu/linux-hwe-edge*

ubuntu/linux-kvm*

ubuntu/linux-oracle*

ubuntu/linux-fips*

ubuntu/linux*

ubuntu/linux-aws*

ubuntu/linux-aws-5.0*

ubuntu/linux-aws-5.3*

ubuntu/linux-aws-5.4*

ubuntu/linux-azure*

ubuntu/linux-azure-4.15*

ubuntu/linux-azure-5.3*

ubuntu/linux-azure-5.4*

ubuntu/linux-azure-edge*

ubuntu/linux-gcp*

ubuntu/linux-gcp-4.15*

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-kvm*

ubuntu/linux-oem*

ubuntu/linux-oracle*

ubuntu/linux-oracle-5.0*

ubuntu/linux-oracle-5.3*

ubuntu/linux-oracle-5.4*

ubuntu/linux-raspi-5.4*

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*

ubuntu/linux-aws*

ubuntu/linux-aws-5.11*

ubuntu/linux-aws-5.13*

ubuntu/linux-aws-5.15<5.15.0-1119.126~20.04.1

5.15.0-1119.126~20.04.1

ubuntu/linux-aws-5.8*

ubuntu/linux-azure*

ubuntu/linux-azure-5.11*

ubuntu/linux-azure-5.13*

ubuntu/linux-azure-5.15<5.15.0-1125.134~20.04.1

5.15.0-1125.134~20.04.1

ubuntu/linux-azure-5.8*

ubuntu/linux-azure-fde*

ubuntu/linux-azure-fde-5.15<5.15.0-1124.133~20.04.1

5.15.0-1124.133~20.04.1

ubuntu/linux-bluefield*

ubuntu/linux-gcp*

ubuntu/linux-gcp-5.11*

ubuntu/linux-gcp-5.13*

ubuntu/linux-gcp-5.15<5.15.0-1120.130~20.04.1

5.15.0-1120.130~20.04.1

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<5.15.0-202.212~20.04.1

5.15.0-202.212~20.04.1

ubuntu/linux-hwe-5.8*

ubuntu/linux-ibm*

ubuntu/linux-ibm-5.15<5.15.0-1113.117~20.04.1

5.15.0-1113.117~20.04.1

ubuntu/linux-intel-5.13*

ubuntu/linux-intel-iotg-5.15<5.15.0-1114.120~20.04.1

5.15.0-1114.120~20.04.1

ubuntu/linux-iot*

ubuntu/linux-kvm*

ubuntu/linux-lowlatency-hwe-5.15<5.15.0-197.207~20.04.1

5.15.0-197.207~20.04.1

ubuntu/linux-nvidia-tegra-5.15<5.15.0-1070.72~20.04.1

5.15.0-1070.72~20.04.1

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<5.15.0-1116.122~20.04.1

5.15.0-1116.122~20.04.1

ubuntu/linux-oracle-5.8*

ubuntu/linux-raspi*

ubuntu/linux-raspi2*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.11*

ubuntu/linux-riscv-5.15<5.15.0-1113.117~20.04.2

5.15.0-1113.117~20.04.2

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<5.15.0-202.212

5.15.0-202.212

ubuntu/linux-allwinner-5.19*

ubuntu/linux-aws<5.15.0-1119.126

5.15.0-1119.126

ubuntu/linux-aws-5.19*

ubuntu/linux-aws-6.2*

ubuntu/linux-aws-6.5*

ubuntu/linux-aws-6.8<6.8.0-1069.74~22.04.1

6.8.0-1069.74~22.04.1

ubuntu/linux-azure<5.15.0-1125.134

5.15.0-1125.134

ubuntu/linux-azure-5.19*

ubuntu/linux-azure-6.2*

ubuntu/linux-azure-6.5*

ubuntu/linux-azure-6.8<6.8.0-1073.82~22.04.1

6.8.0-1073.82~22.04.1

ubuntu/linux-azure-fde<5.15.0-1124.133

5.15.0-1124.133

ubuntu/linux-azure-fde-5.19*

ubuntu/linux-azure-fde-6.2*

ubuntu/linux-azure-fde-6.8<6.8.0-1071.78~22.04.1

6.8.0-1071.78~22.04.1

ubuntu/linux-gcp<5.15.0-1120.130

5.15.0-1120.130

ubuntu/linux-gcp-5.19*

ubuntu/linux-gcp-6.2*

ubuntu/linux-gcp-6.5*

ubuntu/linux-gcp-6.8<6.8.0-1073.81~22.04.1

6.8.0-1073.81~22.04.1

ubuntu/linux-gke<5.15.0-1115.121

5.15.0-1115.121

ubuntu/linux-gkeop<5.15.0-1102.110

5.15.0-1102.110

ubuntu/linux-hwe-5.19*

ubuntu/linux-hwe-6.2*

ubuntu/linux-hwe-6.5*

ubuntu/linux-ibm<5.15.0-1113.117

5.15.0-1113.117

ubuntu/linux-ibm-6.8<6.8.0-1069.70~22.04.1

6.8.0-1069.70~22.04.1

ubuntu/linux-intel-iot-realtime*

ubuntu/linux-intel-iotg<5.15.0-1114.120

5.15.0-1114.120

ubuntu/linux-kvm<5.15.0-1111.116

5.15.0-1111.116

ubuntu/linux-lowlatency<5.15.0-197.207

5.15.0-197.207

ubuntu/linux-lowlatency-hwe-5.19*

ubuntu/linux-lowlatency-hwe-6.2*

ubuntu/linux-lowlatency-hwe-6.5*

ubuntu/linux-lowlatency-hwe-6.8<6.8.0-149.149.1~22.04.1

6.8.0-149.149.1~22.04.1

ubuntu/linux-nvidia<5.15.0-1114.115

5.15.0-1114.115

ubuntu/linux-nvidia-6.2*

ubuntu/linux-nvidia-6.5*

ubuntu/linux-nvidia-6.8*

ubuntu/linux-nvidia-tegra<5.15.0-1070.72

5.15.0-1070.72

ubuntu/linux-nvidia-tegra-igx<5.15.0-1059.59

5.15.0-1059.59

ubuntu/linux-oem-5.17*

ubuntu/linux-oem-6.0*

ubuntu/linux-oem-6.1*

ubuntu/linux-oem-6.5*

ubuntu/linux-oracle<5.15.0-1116.122

5.15.0-1116.122

ubuntu/linux-oracle-6.5*

ubuntu/linux-oracle-6.8<6.8.0-1067.71~22.04.1

6.8.0-1067.71~22.04.1

ubuntu/linux-raspi<5.15.0-1113.116

5.15.0-1113.116

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.19*

ubuntu/linux-riscv-6.5*

ubuntu/linux-starfive-5.19*

ubuntu/linux-starfive-6.2*

ubuntu/linux-starfive-6.5*

ubuntu/linux-xilinx-zynqmp*

ubuntu/linux-bluefield<5.15.0-1103.105

5.15.0-1103.105

ubuntu/linux-intel-iot-realtime<5.15.0-1111.115

5.15.0-1111.115

ubuntu/linux-realtime<5.15.0-1118.127

5.15.0-1118.127

ubuntu/linux-realtime-6.8<6.8.1-1064.65~22.04.1

6.8.1-1064.65~22.04.1

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux-aws-fips<5.15.0-1119.126+fips1

5.15.0-1119.126+fips1

ubuntu/linux-azure-fips<5.15.0-1125.134+fips1

5.15.0-1125.134+fips1

ubuntu/linux-fips<5.15.0-202.212+fips1

5.15.0-202.212+fips1

ubuntu/linux-gcp-fips<5.15.0-1120.130+fips1

5.15.0-1120.130+fips1

ubuntu/linux<6.8.0-149.149

6.8.0-149.149

ubuntu/linux-aws<6.8.0-1069.74

6.8.0-1069.74

ubuntu/linux-aws-6.14*

ubuntu/linux-aws-6.17*

ubuntu/linux-aws-7.0<7.0.0-1017.18~24.04.1

7.0.0-1017.18~24.04.1

ubuntu/linux-azure<6.8.0-1073.82

6.8.0-1073.82

ubuntu/linux-azure-6.11*

ubuntu/linux-azure-6.14*

ubuntu/linux-azure-6.17*

ubuntu/linux-azure-7.0*

ubuntu/linux-azure-fde*

ubuntu/linux-azure-fde-6.14*

ubuntu/linux-azure-fde-6.17*

ubuntu/linux-azure-fde-7.0<7.0.0-1019.19~24.04.1

7.0.0-1019.19~24.04.1

ubuntu/linux-azure-nvidia*

ubuntu/linux-azure-nvidia-6.14*

ubuntu/linux-gcp<6.8.0-1073.81

6.8.0-1073.81

ubuntu/linux-gcp-6.11*

ubuntu/linux-gcp-6.14*

ubuntu/linux-gcp-7.0<7.0.0-1017.19~24.04.1

7.0.0-1017.19~24.04.1

ubuntu/linux-gke<6.8.0-1068.77

6.8.0-1068.77

ubuntu/linux-gkeop<6.8.0-1053.57

6.8.0-1053.57

ubuntu/linux-hwe-6.11*

ubuntu/linux-hwe-6.14*

ubuntu/linux-hwe-6.17*

ubuntu/linux-hwe-7.0<7.0.0-42.42~24.04.1

7.0.0-42.42~24.04.1

ubuntu/linux-ibm<6.8.0-1069.70

6.8.0-1069.70

ubuntu/linux-lowlatency<6.8.0-149.149.1

6.8.0-149.149.1

ubuntu/linux-lowlatency-hwe-6.11*

ubuntu/linux-nvidia<6.8.0-1067.70

6.8.0-1067.70

ubuntu/linux-nvidia-6.11*

ubuntu/linux-nvidia-6.17*

ubuntu/linux-nvidia-7.0*

ubuntu/linux-nvidia-lowlatency*

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<6.8.0-1067.71

6.8.0-1067.71

ubuntu/linux-oracle-6.14*

ubuntu/linux-oracle-6.17*

ubuntu/linux-oracle-7.0<7.0.0-1016.18~24.04.1

7.0.0-1016.18~24.04.1

ubuntu/linux-raspi<6.8.0-1068.72

6.8.0-1068.72

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<7.0.0-42.42.1~24.04.1

7.0.0-42.42.1~24.04.1

ubuntu/linux-vmware<6.8.0-1010.10

6.8.0-1010.10

ubuntu/linux-xilinx*

ubuntu/linux-bluefield<6.8.0-1036.41

6.8.0-1036.41

ubuntu/linux-raspi-realtime<6.8.0-2056.58

6.8.0-2056.58

ubuntu/linux-realtime<6.8.1-1064.65

6.8.1-1064.65

ubuntu/linux-realtime-6.14*

ubuntu/linux-realtime-6.17*

ubuntu/linux-aws-fips<6.8.0-1069.74+fips1

6.8.0-1069.74+fips1

ubuntu/linux-azure-fips<6.8.0-1073.82+fips1

6.8.0-1073.82+fips1

ubuntu/linux-fips*

ubuntu/linux-gcp-fips<6.8.0-1073.81+fips1

6.8.0-1073.81+fips1

ubuntu/linux<7.0.0-42.42

7.0.0-42.42

ubuntu/linux-aws<7.0.0-1016.17

7.0.0-1016.17

ubuntu/linux-azure<7.0.0-1020.21

7.0.0-1020.21

ubuntu/linux-azure-fde<7.0.0-1019.19

7.0.0-1019.19

ubuntu/linux-gcp<7.0.0-1016.18

7.0.0-1016.18

ubuntu/linux-gke<7.0.0-1010.11

7.0.0-1010.11

ubuntu/linux-ibm<7.0.0-1017.17

7.0.0-1017.17

ubuntu/linux-nvidia*

ubuntu/linux-nvidia-bos*

ubuntu/linux-oem-7.0<7.0.0-1017.17

7.0.0-1017.17

ubuntu/linux-oracle<7.0.0-1015.16

7.0.0-1015.16

ubuntu/linux-raspi*

ubuntu/linux-realtime<7.0.0-43.43.1

7.0.0-43.43.1

ubuntu/linux-riscv<7.0.0-42.42.1

7.0.0-42.42.1

ubuntu/linux-vmware*

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 6.6.157.1-1
Upgrade
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Fixed in 6.1.190-1Fixed in 6.12.116-1Fixed in 7.2.15-1Fixed in 7.3.3-1
Upgrade
Upgrade debian/linux-6.12 to a version that resolves this vulnerability.
Fixed in 6.12.115-2~deb12u1
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Fixed in 5.15.0-1119.126~20.04.1
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Fixed in 5.15.0-1125.134~20.04.1
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Fixed in 5.15.0-1124.133~20.04.1
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Fixed in 5.15.0-1120.130~20.04.1
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Fixed in 5.15.0-202.212~20.04.1
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Fixed in 5.15.0-1113.117~20.04.1
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Fixed in 5.15.0-1114.120~20.04.1
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Fixed in 5.15.0-197.207~20.04.1
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Fixed in 5.15.0-1070.72~20.04.1
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Fixed in 5.15.0-1116.122~20.04.1
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Fixed in 5.15.0-1113.117~20.04.2
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Fixed in 5.15.0-202.212
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Fixed in 5.15.0-1119.126
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Fixed in 6.8.0-1069.74~22.04.1
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Fixed in 5.15.0-1125.134
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Fixed in 6.8.0-1073.82~22.04.1
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Fixed in 5.15.0-1124.133
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Fixed in 6.8.0-1071.78~22.04.1
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Fixed in 5.15.0-1120.130
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Fixed in 6.8.0-1073.81~22.04.1
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Fixed in 5.15.0-1115.121
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Fixed in 5.15.0-1102.110
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Fixed in 5.15.0-1113.117
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Fixed in 6.8.0-1069.70~22.04.1
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Fixed in 5.15.0-1114.120
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Fixed in 5.15.0-1111.116
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Fixed in 5.15.0-197.207
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Fixed in 6.8.0-149.149.1~22.04.1
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Fixed in 5.15.0-1114.115
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Fixed in 5.15.0-1070.72
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Fixed in 5.15.0-1059.59
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Fixed in 5.15.0-1116.122
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Fixed in 6.8.0-1067.71~22.04.1
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Fixed in 5.15.0-1113.116
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Fixed in 5.15.0-1103.105
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Fixed in 5.15.0-1111.115
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Fixed in 5.15.0-1118.127
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Fixed in 6.8.1-1064.65~22.04.1
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Fixed in 5.15.0-1119.126+fips1
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Fixed in 5.15.0-1125.134+fips1
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Fixed in 5.15.0-202.212+fips1
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Fixed in 5.15.0-1120.130+fips1
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Fixed in 6.8.0-149.149
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Fixed in 6.8.0-1069.74
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Fixed in 7.0.0-1017.18~24.04.1
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Fixed in 6.8.0-1073.82
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Fixed in 7.0.0-1019.19~24.04.1
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Fixed in 6.8.0-1073.81
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Fixed in 7.0.0-1017.19~24.04.1
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Fixed in 6.8.0-1068.77
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Fixed in 6.8.0-1053.57
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Fixed in 7.0.0-42.42~24.04.1
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Fixed in 6.8.0-1069.70
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Fixed in 6.8.0-149.149.1
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Fixed in 6.8.0-1067.70
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Fixed in 6.8.0-1067.71
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Fixed in 7.0.0-1016.18~24.04.1
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Fixed in 6.8.0-1068.72
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Fixed in 7.0.0-42.42.1~24.04.1
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Fixed in 6.8.0-1010.10
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Fixed in 6.8.0-1036.41
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Fixed in 6.8.0-2056.58
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Fixed in 6.8.1-1064.65
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Fixed in 6.8.0-1069.74+fips1
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Fixed in 6.8.0-1073.82+fips1
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Fixed in 6.8.0-1073.81+fips1
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Fixed in 7.0.0-42.42
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Fixed in 7.0.0-1016.17
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Fixed in 7.0.0-1020.21
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Fixed in 7.0.0-1019.19
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Fixed in 7.0.0-1016.18
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Fixed in 7.0.0-1010.11
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Fixed in 7.0.0-1017.17
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Fixed in 7.0.0-1017.17
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Fixed in 7.0.0-1015.16
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Fixed in 7.0.0-43.43.1
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Fixed in 7.0.0-42.42.1

Event History

Sep 16, 2026

CVE Published

via MITRE·08:48 AM

Data Sourced

via MITRE·08:48 AM

Description

Data Sourced

via OSV·09:17 AM

DescriptionSeverityAffected Software

Data Sourced

via NVD·09:17 AM

Description

Sep 17, 2026

Data Sourced

via Microsoft·08:06 AM

DescriptionSeverityWeaknessAffected Software

Parent advisories

This vulnerability appears in the following advisories.

DSA-6528

Peer vulnerabilities

Found alongside the following vulnerabilities.

Frequently Asked Questions

What conditions are required to trigger the kernel crash?

The failure requires rpc_sockaddr2uaddr() to return NULL because its final kstrdup() allocation fails while rpcb_register_inet4() or rpcb_register_inet6() is registering with RPCBPROC_SET. The unchecked NULL then reaches encode_rpcb_string(), which calls strlen() on it and oopses the kernel.

Is this issue remotely exploitable based on the available information?

The provided information describes an allocation-failure path during local kernel SUNRPC processing and demonstrates reproduction with failslab. It does not establish a remote trigger or identify an attacker-controlled input that can force the allocation failure.

How can I determine whether a system has encountered this issue?

Look for a kernel oops with strlen in the call trace, followed by encode_rpcb_string, rpcb_enc_getaddr, rpc_call_sync, and RPC bind registration functions. With KASAN, the report may appear as a general protection fault involving the shadow of address zero.

What is the immediate mitigation if an updated kernel cannot be deployed?

The supplied data does not provide a configuration workaround. The described trigger depends on a memory-allocation failure during SUNRPC RPC bind registration, so avoid relying on unverified mitigations and plan to deploy a kernel containing the referenced fix.

CVE-2026-89784: SUNRPC: check rpc_sockaddr2uaddr() return value in rpcb_register_inet4/6

Affected Software

Remediation

Event History

Parent advisories

Peer vulnerabilities

Frequently Asked Questions

What conditions are required to trigger the kernel crash?

Is this issue remotely exploitable based on the available information?

How can I determine whether a system has encountered this issue?

What is the immediate mitigation if an updated kernel cannot be deployed?

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