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Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: Only allow act_ct to bind to clsact/ingress qdiscs and shared blocks As Paolo said earlier [1]: "Since the blamed commit below, classify can return TC_ACT_CONSUMED while the current skb being held by the defragmentation engine. As reported by GangMin Kim, if such packet is that may cause a UaF when the defrag engine later on tries to tuch again such packet." act_ct was never meant to be used in the egress path, however some users are attaching it to egress today [2]. Attempting to reach a middle ground, we noticed that, while most qdiscs are not handling TC_ACT_CONSUMED, clsact/ingress qdiscs are. With that in mind, we address the issue by only allowing act_ct to bind to clsact/ingress qdiscs and shared blocks. That way it's still possible to attach act_ct to egress (albeit only with clsact). [1] https://lore.kernel.org/netdev/674b8cbfc385c6f37fb29a1de08d8fe5c2b0fbee.1771321118.git.pabeni@redhat.com/ [2] https://lore.kernel.org/netdev/cc6bfb4a-4a2b-42d8-b9ce-7ef6644fb22b@ovn.org/

PUBLISHED Reserved 2026-01-13 | Published 2026-03-18 | Updated 2026-04-18 | Assigner Linux




HIGH: 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Product status

Default status
unaffected

172ba7d46c202e679f3ccb10264c67416aaeb1c4 (git) before bc4e5bb529823a09f02dbe96169de679a9db26e0
affected

0b5b831122fc3789fff75be433ba3e4dd7b779d4 (git) before fb3c380a54e33d1fd272cc342faa906d787d7ef1
affected

73f7da5fd124f2cda9161e2e46114915e6e82e97 (git) before 5a110ddcc99bda77a28598b3555fe009eaab3828
affected

3f14b377d01d8357eba032b4cabc8c1149b458b6 (git) before 524ce8b4ea8f64900b6c52b6a28df74f6bc0801e
affected

3f14b377d01d8357eba032b4cabc8c1149b458b6 (git) before 380ad8b7c65ea7aa10ef2258297079ed5ac1f5b6
affected

3f14b377d01d8357eba032b4cabc8c1149b458b6 (git) before 9deda0fcda5c1f388c5e279541850b71a2ccfcf4
affected

3f14b377d01d8357eba032b4cabc8c1149b458b6 (git) before 11cb63b0d1a0685e0831ae3c77223e002ef18189
affected

f5346df0591d10bc948761ca854b1fae6d2ef441 (git)
affected

Default status
affected

6.8
affected

Any version before 6.8
unaffected

5.15.203 (semver)
unaffected

6.1.167 (semver)
unaffected

6.6.130 (semver)
unaffected

6.12.77 (semver)
unaffected

6.18.18 (semver)
unaffected

6.19.8 (semver)
unaffected

7.0 (original_commit_for_fix)
unaffected

References

git.kernel.org/...c/bc4e5bb529823a09f02dbe96169de679a9db26e0

git.kernel.org/...c/fb3c380a54e33d1fd272cc342faa906d787d7ef1

git.kernel.org/...c/5a110ddcc99bda77a28598b3555fe009eaab3828

git.kernel.org/...c/524ce8b4ea8f64900b6c52b6a28df74f6bc0801e

git.kernel.org/...c/380ad8b7c65ea7aa10ef2258297079ed5ac1f5b6

git.kernel.org/...c/9deda0fcda5c1f388c5e279541850b71a2ccfcf4

git.kernel.org/...c/11cb63b0d1a0685e0831ae3c77223e002ef18189

cve.org (CVE-2026-23270)

nvd.nist.gov (CVE-2026-23270)

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