CVE-2026-31630 Affecting linux-6.1 package, versions <6.1.176-1~deb11u1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.18% (7th percentile)

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  • Snyk IDSNYK-DEBIAN11-LINUX61-17818299
  • published6 Jul 2026
  • disclosed24 Apr 2026

Introduced: 24 Apr 2026

CVE-2026-31630  (opens in a new tab)

How to fix?

Upgrade Debian:11 linux-6.1 to version 6.1.176-1~deb11u1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream linux-6.1 package and not the linux-6.1 package as distributed by Debian. See How to fix? for Debian:11 relevant fixed versions and status.

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

rxrpc: proc: size address buffers for %pISpc output

The AF_RXRPC procfs helpers format local and remote socket addresses into fixed 50-byte stack buffers with "%pISpc".

That is too small for the longest current-tree IPv6-with-port form the formatter can produce. In lib/vsprintf.c, the compressed IPv6 path uses a dotted-quad tail not only for v4mapped addresses, but also for ISATAP addresses via ipv6_addr_is_isatap().

As a result, a case such as

is possible with the current formatter. That is 50 visible characters, so 51 bytes including the trailing NUL, which does not fit in the existing char[50] buffers used by net/rxrpc/proc.c.

Size the buffers from the formatter's maximum textual form and switch the call sites to scnprintf().

Changes since v1:

  • correct the changelog to cite the actual maximum current-tree case explicitly
  • frame the proof around the ISATAP formatting path instead of the earlier mapped-v4 example

CVSS Base Scores

version 3.1