CVE-2026-98012

Name	CVE-2026-98012
Description	In the Linux kernel, the following vulnerability has been resolved: net/sched: sfq: clamp quantum in change path sfq_change() accepts any non-negative quantum (only rejects (int)ctl->quantum < 0). With a crafted size table qdisc_pkt_len reaches ~2 GiB, so quantum=1 makes the deficit-refill loop spin ~2^31 times under the qdisc lock (a soft lockup / denial of service). Add max(256U, ...) matching fq_codel_change(). Reject quantum > 1<<20 with -EINVAL, matching fq_codel_change() and the init clamp. Conditions to recreate the bug: CONFIG_NET_SCH_SFQ=y. Requires CAP_NET_ADMIN (namespace-local via unshare -Urn suffices). tc qdisc add dev dummy0 root sfq tc qdisc change dev dummy0 root sfq quantum 1 stab data 32768 size_log 15 cell_log 0
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)
References	DLA-4817-1, DSA-6528-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
linux (PTS)	bookworm	6.1.176-1	vulnerable
	bookworm (security)	6.1.187-1	vulnerable
	trixie	6.12.107-1	vulnerable
	trixie (security)	6.12.111-1	fixed
	forky	7.2.9-1	fixed
	sid	7.2.10-1	fixed
linux-6.12 (PTS)	bookworm (security)	6.12.111-1~deb12u1	fixed

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

Package	Type	Release	Fixed Version	Origin
linux	source	trixie	6.12.111-1	DSA-6528-1
linux	source	(unstable)	7.2.7-1
linux-6.12	source	bookworm	6.12.111-1~deb12u1	DLA-4817-1

https://git.kernel.org/linus/fb9f88a33c516ea5c0bcd9a22ca288b246b34567 (7.3-rc3)