CVE-2026-23255net: add proper RCU protection to /proc/net/ptype
- 5.5MediumCVSS base score
- 0.13%Exploitation in 30 daysEPSS · top 97% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By Linux
- 2 months later
· 2 months later
Published
- 8 months later
· 8 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | Medium5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.13% · top 97% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.5.
Affected products
- affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – < e974a10a52618f7f57a4bce173a0ed96acd4e5dc
- affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – < 002a73470b56848e4c81efeaaedd471e92d66d8d
- affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – < dcefd3f0b9ed8288654c75254bdcee8e1085e861
- affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – < 589a530ae44d0c80f523fcfd1a15af8087f27d35
- affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – < f613e8b4afea0cd17c7168e8b00e25bc8d33175d
- affected 2.6.12
- unaffected < 2.6.12
- unaffected 6.1.175 – ≤ 6.1.*
- unaffected 6.6.136 – ≤ 6.6.*
- unaffected 6.12.80 – ≤ 6.12.*
- unaffected 6.18.10 – ≤ 6.18.*
- unaffected 6.19 – ≤ *
References
References8
- https://git.kernel.org/stable/c/e974a10a52618f7f57a4bce173a0ed96acd4e5dc (opens in a new tab)
- https://git.kernel.org/stable/c/002a73470b56848e4c81efeaaedd471e92d66d8d (opens in a new tab)
- https://git.kernel.org/stable/c/dcefd3f0b9ed8288654c75254bdcee8e1085e861 (opens in a new tab)
- https://git.kernel.org/stable/c/589a530ae44d0c80f523fcfd1a15af8087f27d35 (opens in a new tab)
- https://git.kernel.org/stable/c/f613e8b4afea0cd17c7168e8b00e25bc8d33175d (opens in a new tab)
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html (opens in a new tab)
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html (opens in a new tab)
- https://cert-portal.siemens.com/productcert/html/ssa-784472.html (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-12886 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-23255)Record last updated .