🛡️ UBUNTU-CVE-2026-31402
⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix heap overflow in NFSv4.0 LOCK replay cache The NFSv4.0 replay cache uses a fixed 112-byte inline buffer (rp_ibuf[NFSD4_REPLAY_ISIZE]) to store encoded operation responses. This size was calculated based on OPEN responses and does not account for LOCK denied responses, which include the conflicting lock owner as a variable-length field up to 1024 bytes (NFS4_OPAQUE_LIMIT). When a LOCK operation is denied due to a conflict with an existing lock that has a large owner, nfsd4_encode_operation() copies the full encoded response into the undersized replay buffer via read_bytes_from_xdr_buf() with no bounds check. This results in a slab-out-of-bounds write of up to 944 bytes past the end of the buffer, corrupting adjacent heap memory. This can be triggered remotely by an unauthenticated attacker with two cooperating NFSv4.0 clients: one sets a lock with a large owner string, then the other requests a conflicting lock to provoke the denial. We could fix this by increasing NFSD4_REPLAY_ISIZE to allow for a full opaque, but that would increase the size of every stateowner, when most lockowners are not that large. Instead, fix this by checking the encoded response length against NFSD4_REPLAY_ISIZE before copying into the replay buffer. If the response is too large, set rp_buflen to 0 to skip caching the replay payload. The status is still cached, and the client already received the correct response on the original request.

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-04-03
Updated 2026-06-13
Modified 2026-06-12
Fix URL N/A

Affected Packages

Software From version Fixed in
linux
linux-allwinner-5.19
linux-aws
linux-aws-5.0
linux-aws-5.11
linux-aws-5.13
linux-aws-5.15
linux-aws-5.19
linux-aws-5.3
linux-aws-5.4
linux-aws-5.8
linux-aws-6.14
linux-aws-6.17
linux-aws-6.2
linux-aws-6.5
linux-aws-6.8
linux-aws-fips
linux-aws-hwe
linux-azure
linux-azure-4.15
linux-azure-5.11
linux-azure-5.13
linux-azure-5.15
linux-azure-5.19
linux-azure-5.3
linux-azure-5.4
linux-azure-5.8
linux-azure-6.11
linux-azure-6.14
linux-azure-6.17
linux-azure-6.2
linux-azure-6.5
linux-azure-6.8
linux-azure-edge
linux-azure-fde
linux-azure-fde-5.19
linux-azure-fde-6.14
linux-azure-fde-6.17
linux-azure-fde-6.2
linux-azure-fde-6.8
linux-azure-fips
linux-azure-nvidia
linux-azure-nvidia-6.14
linux-bluefield
linux-fips
linux-gcp
linux-gcp-4.15
linux-gcp-5.11
linux-gcp-5.13
linux-gcp-5.15
linux-gcp-5.19
linux-gcp-5.3
linux-gcp-5.4
linux-gcp-5.8
linux-gcp-6.11
linux-gcp-6.14
linux-gcp-6.17
linux-gcp-6.2
linux-gcp-6.5
linux-gcp-6.8
linux-gcp-fips
linux-gke
linux-gke-4.15
linux-gke-5.15
linux-gke-5.4
linux-gkeop
linux-gkeop-5.15
linux-gkeop-5.4
linux-hwe
linux-hwe-5.11
linux-hwe-5.13
linux-hwe-5.15
linux-hwe-5.19
linux-hwe-5.4
linux-hwe-5.8
linux-hwe-6.11
linux-hwe-6.14
linux-hwe-6.17
linux-hwe-6.2
linux-hwe-6.5
linux-hwe-6.8
linux-hwe-edge
linux-ibm
linux-ibm-5.15
linux-ibm-5.4
linux-ibm-6.8
linux-intel-5.13
linux-intel-iot-realtime
linux-intel-iotg
linux-intel-iotg-5.15
linux-iot
linux-kvm
linux-lowlatency
linux-lowlatency-hwe-5.15
linux-lowlatency-hwe-5.19
linux-lowlatency-hwe-6.11
linux-lowlatency-hwe-6.2
linux-lowlatency-hwe-6.5
linux-lowlatency-hwe-6.8
linux-lts-xenial
linux-nvidia
linux-nvidia-6.11
linux-nvidia-6.17
linux-nvidia-6.2
linux-nvidia-6.5
linux-nvidia-6.8
linux-nvidia-lowlatency
linux-nvidia-tegra
linux-nvidia-tegra-5.15
linux-nvidia-tegra-igx
linux-oem
linux-oem-5.10
linux-oem-5.13
linux-oem-5.14
linux-oem-5.17
linux-oem-5.6
linux-oem-6.0
linux-oem-6.1
linux-oem-6.11
linux-oem-6.14
linux-oem-6.17
linux-oem-6.5
linux-oem-6.8
linux-oracle
linux-oracle-5.0
linux-oracle-5.11
linux-oracle-5.13
linux-oracle-5.15
linux-oracle-5.3
linux-oracle-5.4
linux-oracle-5.8
linux-oracle-6.14
linux-oracle-6.17
linux-oracle-6.5
linux-oracle-6.8
linux-raspi
linux-raspi-5.4
linux-raspi-realtime
linux-raspi2
linux-realtime
linux-realtime-6.14
linux-realtime-6.17
linux-realtime-6.8
linux-riscv
linux-riscv-5.11
linux-riscv-5.15
linux-riscv-5.19
linux-riscv-5.8
linux-riscv-6.14
linux-riscv-6.17
linux-riscv-6.5
linux-riscv-6.8
linux-starfive-5.19
linux-starfive-6.2
linux-starfive-6.5
linux-xilinx
linux-xilinx-zynqmp

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