CVE-2026-23255
Description
In the Linux kernel, the following vulnerability has been resolved: net: add proper RCU protection to /proc/net/ptype Yin Fengwei reported an RCU stall in ptype_seq_show() and provided a patch. Real issue is that ptype_seq_next() and ptype_seq_show() violate RCU rules. ptype_seq_show() runs under rcu_read_lock(), and reads pt->dev to get device name without any barrier. At the same time, concurrent writers can remove a packet_type structure (which is correctly freed after an RCU grace period) and clear pt->dev without an RCU grace period. Define ptype_iter_state to carry a dev pointer along seq_net_private: struct ptype_iter_state { struct seq_net_private p; struct net_device *dev; // added in this patch }; We need to record the device pointer in ptype_get_idx() and ptype_seq_next() so that ptype_seq_show() is safe against concurrent pt->dev changes. We also need to add full RCU protection in ptype_seq_next(). (Missing READ_ONCE() when reading list.next values) Many thanks to Dong Chenchen for providing a repro.
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
Linux kernel Affected 3 releases
| Version | Status | Fixed in |
|---|---|---|
| 6.19 | Affected | — |
| 2.6.12 | Affected | — |
| — | Affected | 6.6.136 |
SUSE Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Debian Mixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Fixed | 6.12.85-1 |
| sid | Fixed | 6.18.10-1 |
| forky | Fixed | 6.18.10-1 |
| bullseye | Affected | — |
| bookworm | Affected | — |
Application impact
| Vendor | Product | Versions | Fixed |
|---|---|---|---|
| gcp | | |
References
- https://git.kernel.org/stable/c/002a73470b56848e4c81efeaaedd471e92d66d8d
- https://git.kernel.org/stable/c/589a530ae44d0c80f523fcfd1a15af8087f27d35
- https://git.kernel.org/stable/c/dcefd3f0b9ed8288654c75254bdcee8e1085e861
- https://git.kernel.org/stable/c/f613e8b4afea0cd17c7168e8b00e25bc8d33175d
- https://www.suse.com/security/cve/CVE-2026-23255.html
- https://security-tracker.debian.org/tracker/CVE-2026-23255
- https://git.kernel.org/stable/c/e974a10a52618f7f57a4bce173a0ed96acd4e5dc
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.