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Fencer Vulns
medium 5.5

CVE-2026-22983 json

net: do not write to msg_get_inq in callee

published 2026-01-23 9 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-4320

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 1%
public exploits
0
none known

Summary

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

net: do not write to msg_get_inq in callee

NULL pointer dereference fix.

msg_get_inq is an input field from caller to callee. Don't set it in the callee, as the caller may not clear it on struct reuse.

This is a kernel-internal variant of msghdr only, and the only user does reinitialize the field. So this is not critical for that reason. But it is more robust to avoid the write, and slightly simpler code. And it fixes a bug, see below.

Callers set msg_get_inq to request the input queue length to be returned in msg_inq. This is equivalent to but independent from the SO_INQ request to return that same info as a cmsg (tp->recvmsg_inq). To reduce branching in the hot path the second also sets the msg_inq. That is WAI.

This is a fix to commit 4d1442979e4a ("af_unix: don't post cmsg for SO_INQ unless explicitly asked for"), which fixed the inverse.

Also avoid NULL pointer dereference in unix_stream_read_generic if state->msg is NULL and msg->msg_get_inq is written. A NULL state->msg can happen when splicing as of commit 2b514574f7e8 ("net: af_unix: implement splice for stream af_unix sockets").

Also collapse two branches using a bitwise or.

Patch / fix

  • Linux Linux 6.18.6
  • linux Debian 14 6.18.8-1

debian advisories DEBIAN-CVE-2026-22983

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-22983 updated cvss 5.5

kernel: net: do not write to msg_get_inq in callee

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.12% chance of exploitation in the next 30 days, higher than 1% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Weakness
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.