In the Linux kernel, the following vulnerability has been resolved: netfs: Fix kernel BUG in...

CVE-2026-31438 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

Description

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

netfs: Fix kernel BUG in netfs_limit_iter() for ITER_KVEC iterators

When a process crashes and the kernel writes a core dump to a 9P
filesystem, __kernel_write() creates an ITER_KVEC iterator. This
iterator reaches netfs_limit_iter() via netfs_unbuffered_write(), which
only handles ITER_FOLIOQ, ITER_BVEC and ITER_XARRAY iterator types,
hitting the BUG() for any other type.

Fix this by adding netfs_limit_kvec() following the same pattern as
netfs_limit_bvec(), since both kvec and bvec are simple segment arrays
with pointer and length fields. Dispatch it from netfs_limit_iter() when
the iterator type is ITER_KVEC.

Basic information

Type
unreviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
—
Source code
Not specified
Published (advisory)
2026-04-22 15:31:40 UTC
Updated
2026-05-20 00:31:40 UTC
NVD published
2026-04-22

EPSS Score

Score Percentile
0.01% 2.06%

CVSS Scores

Base score Version Severity Vector
5.5 3.1 —
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.

Identifiers

Type Value
GHSA GHSA-3jp7-x2f9-j2c3 ↗
CVE CVE-2026-31438 ↗

CWEs

CWE id Name
CWE-476 NULL Pointer Dereference

References

cvelogic Threat Intelligence