CVE-2026-23247

Name	CVE-2026-23247
Description	In the Linux kernel, the following vulnerability has been resolved: tcp: secure_seq: add back ports to TS offset This reverts 28ee1b746f49 ("secure_seq: downgrade to per-host timestamp offsets") tcp_tw_recycle went away in 2017. Zhouyan Deng reported off-path TCP source port leakage via SYN cookie side-channel that can be fixed in multiple ways. One of them is to bring back TCP ports in TS offset randomization. As a bonus, we perform a single siphash() computation to provide both an ISN and a TS offset.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
linux (PTS)	bullseye	5.10.223-1	vulnerable
	bullseye (security)	5.10.251-1	vulnerable
	bookworm	6.1.159-1	vulnerable
	bookworm (security)	6.1.164-1	vulnerable
	trixie	6.12.73-1	vulnerable
	trixie (security)	6.12.74-2	vulnerable
	forky	6.19.10-1	fixed
	sid	6.19.11-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
linux	source	(unstable)	6.19.8-1

https://git.kernel.org/linus/165573e41f2f66ef98940cf65f838b2cb575d9d1 (7.0-rc3)