CVE-2026-31422
Description
In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_flow: fix NULL pointer dereference on shared blocks flow_change() calls tcf_block_q() and dereferences q->handle to derive a default baseclass. Shared blocks leave block->q NULL, causing a NULL deref when a flow filter without a fully qualified baseclass is created on a shared block. Check tcf_block_shared() before accessing block->q and return -EINVAL for shared blocks. This avoids the null-deref shown below: ======================================================================= KASAN: null-ptr-deref in range [0x0000000000000038-0x000000000000003f] RIP: 0010:flow_change (net/sched/cls_flow.c:508) Call Trace: tc_new_tfilter (net/sched/cls_api.c:2432) rtnetlink_rcv_msg (net/core/rtnetlink.c:6980) [...] =======================================================================
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| sles | affected | | |
| debian | bookworm | fixed | 6.1.170-1 |
| debian | bullseye | fixed | 6.1.170-1~deb11u1 |
| debian | forky | fixed | 6.19.12-1 |
| debian | sid | fixed | 6.19.12-1 |
| debian | trixie | fixed | 6.12.85-1 |
| linux-kernel | affected | 5.10.253 | |
| linux-kernel | 7.0 | affected | |
References
- https://git.kernel.org/stable/c/1a280dd4bd1d616a01d6ffe0de284c907b555504
- https://git.kernel.org/stable/c/415ea0c973c754b9f375225807810eb9045f4293
- https://git.kernel.org/stable/c/4a09f72007201c9f667dc47f64517ec23eea65e5
- https://git.kernel.org/stable/c/57f94ac7e953eece5ed4819605a18f3cdfc63dcc
- https://git.kernel.org/stable/c/942813276edeb1741fa5b0a73471beb4e495fa08
- https://git.kernel.org/stable/c/9bf5fc36a43f7b8b5507c96e74fb81f1e8b4957e
- https://git.kernel.org/stable/c/a208c3e1232997e9317887294c20008dfcb75449
- https://git.kernel.org/stable/c/cc707a4fd4c3b6ab2722e06bc359aa010e13d408
- https://www.suse.com/security/cve/CVE-2026-31422.html
- https://security-tracker.debian.org/tracker/CVE-2026-31422
CWEs
CWE-476
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.