Description
In the Linux kernel, the following vulnerability has been resolved: net_sched: red: fix a race in __red_change() Gerrard Tai reported a race condition in RED, whenever SFQ perturb timer fires at the wrong time. The race is as follows: CPU 0 CPU 1 [1]: lock root [2]: qdisc_tree_flush_backlog() [3]: unlock root | | [5]: lock root | [6]: rehash | [7]: qdisc_tree_reduce_backlog() | [4]: qdisc_put() This can be abused to underflow a parent's qlen. Calling qdisc_purge_queue() instead of qdisc_tree_flush_backlog() should fix the race, because all packets will be purged from the qdisc before releasing the lock.
Product status
0c8d13ac96070000da33f394f45e9c19638483c5 (git) before 2790c4ec481be45a80948d059cd7c9a06bc37493
0c8d13ac96070000da33f394f45e9c19638483c5 (git) before a1bf6a4e9264a685b0e642994031f9c5aad72414
0c8d13ac96070000da33f394f45e9c19638483c5 (git) before 110a47efcf23438ff8d31dbd9c854fae2a48bf98
0c8d13ac96070000da33f394f45e9c19638483c5 (git) before f569984417a4e12c67366e69bdcb752970de921d
0c8d13ac96070000da33f394f45e9c19638483c5 (git) before 2a71924ca4af59ffc00f0444732b6cd54b153d0e
0c8d13ac96070000da33f394f45e9c19638483c5 (git) before 4b755305b2b0618e857fdadb499365b5f2e478d1
0c8d13ac96070000da33f394f45e9c19638483c5 (git) before 444ad445df5496a785705019268a8a84b84484bb
0c8d13ac96070000da33f394f45e9c19638483c5 (git) before 85a3e0ede38450ea3053b8c45d28cf55208409b8
5.0
Any version before 5.0
5.4.295 (semver)
5.10.239 (semver)
5.15.186 (semver)
6.1.142 (semver)
6.6.94 (semver)
6.12.34 (semver)
6.15.3 (semver)
6.16 (original_commit_for_fix)
References
lists.debian.org/debian-lts-announce/2025/10/msg00008.html
lists.debian.org/debian-lts-announce/2025/10/msg00007.html
git.kernel.org/...c/2790c4ec481be45a80948d059cd7c9a06bc37493
git.kernel.org/...c/a1bf6a4e9264a685b0e642994031f9c5aad72414
git.kernel.org/...c/110a47efcf23438ff8d31dbd9c854fae2a48bf98
git.kernel.org/...c/f569984417a4e12c67366e69bdcb752970de921d
git.kernel.org/...c/2a71924ca4af59ffc00f0444732b6cd54b153d0e
git.kernel.org/...c/4b755305b2b0618e857fdadb499365b5f2e478d1
git.kernel.org/...c/444ad445df5496a785705019268a8a84b84484bb
git.kernel.org/...c/85a3e0ede38450ea3053b8c45d28cf55208409b8