CVE-2026-53238

What the bug is

netlbl_unlabel_addrinfo_get() used the address attribute length to determine whether the attribute data could be read as an IPv4 or IPv6 address, but did not independently validate the corresponding mask attribute length. A crafted Generic Netlink request could therefore provide a valid IPv4/IPv6 address attribute with a shorter mask attribute, which would later be read as a full struct in_addr or struct in6_addr. NLA_BINARY policy lengths are maximum lengths by default, so use NLA_POLICY_EXACT_LEN() for the unlabeled IPv4/IPv6 address and mask attributes. This rejects short attributes during policy validation and also exposes the exact length requirements through policy introspection.

Where it lives

The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.

net/netlabel/netlabel_unlabeled.c

What this is

NETWORKING [LABELED] (NetLabel, Labeled IPsec, SECMARK)MAINTAINERS section matched on net/netlabel/ · netdev@vger.kernel.org · Supported

Check it on the machine

grep -w CONFIG_NETLABEL /boot/config-$(uname -r)

Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.

Show whether Debian builds this, per release

Debian builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.

• bookwormy
• trixieYnot built on armel/rpi
• forky, sidy

y

built into the kernel image on every flavour - only a patch removes it

Y

built in where it is built at all; some flavours do not build it

Build switch

CONFIG_NETLABEL

From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages

Signals

Published

2026-06-25 (4 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.12%, higher than 1.8% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

net/netlabel

Upstream fixes

The versions the CNA records as introducing and fixing this, and the commit for each. source

Introduced	Fixed in	Commit
2.6.25	5.10.259	975a84fd7414
2.6.25	5.15.210	672f0f3b8f87
2.6.25	6.1.176	95bda3eac0b1
2.6.25	6.6.143	07a18f5c90dd
2.6.25	6.12.94	71c52da13c37
2.6.25	6.18.36	0c4bb32ad7fd
2.6.25	7.0.13	ccfe292a9660
2.6.25	7.1	9772589b57e4

Debian advisories