CVE-2026-31437

MEDIUM EPSS 2.2%
Published Apr 22, 20262mo ago · Modified Jun 17, 20262w ago
5.5 CVSS 3.1
Medium
Find Similar
Published Apr 22, 2026 2mo ago
Last Modified Jun 17, 2026 2w ago

Description

In the Linux kernel, the following vulnerability has been resolved: netfs: Fix NULL pointer dereference in netfs_unbuffered_write() on retry When a write subrequest is marked NETFS_SREQ_NEED_RETRY, the retry path in netfs_unbuffered_write() unconditionally calls stream->prepare_write() without checking if it is NULL. Filesystems such as 9P do not set the prepare_write operation, so stream->prepare_write remains NULL. When get_user_pages() fails with -EFAULT and the subrequest is flagged for retry, this results in a NULL pointer dereference at fs/netfs/direct_write.c:189. Fix this by mirroring the pattern already used in write_retry.c: if stream->prepare_write is NULL, skip renegotiation and directly reissue the subrequest via netfs_reissue_write(), which handles iterator reset, IN_PROGRESS flag, stats update and reissue internally.

CVSS Details

Base Score
5.5
Exploitability
1.8
Impact
3.6
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
2.2% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-476 NULL Pointer Dereference Memory Safety

Affected Products 2

VendorProductVersionRange
linuxlinux_kernel*≥6.18.17  –  <6.18.21
linuxlinux_kernel*≥6.19.7  –  <6.19.11

References 3

  • git.kernel.org https://git.kernel.org/stable/c/7a5482f5ce891decbf36f2e6fab1e9fc4a76a684
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/a4d1b4ba9754bac3efebd06f583a44a7af52c0ab
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/e9075e420a1eb3b52c60f3b95893a55e77419ce8
    Patch

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/7a5482f5ce891decbf36f2e6fab1e9fc4a76a684
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/a4d1b4ba9754bac3efebd06f583a44a7af52c0ab
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/e9075e420a1eb3b52c60f3b95893a55e77419ce8
    Patch