CVE-2021-47223
net: bridge: fix vlan tunnel dst null pointer dereference
- Published
- Updated
- Reserved
- Assigned by
- Linux
Description
In the Linux kernel, the following vulnerability has been resolved: net: bridge: fix vlan tunnel dst null pointer dereference This patch fixes a tunnel_dst null pointer dereference due to lockless access in the tunnel egress path. When deleting a vlan tunnel the tunnel_dst pointer is set to NULL without waiting a grace period (i.e. while it's still usable) and packets egressing are dereferencing it without checking. Use READ/WRITE_ONCE to annotate the lockless use of tunnel_id, use RCU for accessing tunnel_dst and make sure it is read only once and checked in the egress path. The dst is already properly RCU protected so we don't need to do anything fancy than to make sure tunnel_id and tunnel_dst are read only once and checked in the egress path.
Timeline
ID reserved
By Linux
- 41 days later
· 41 days later
Published
- 24 months later
· 24 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 · Analyzed | 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)
- 0.24% · top 85% of all CVEs (7 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.
Weakness
Affected products
- affected 11538d039ac6efcf4f1a6c536e1b87cd3668a9fd – < ad7feefe7164892db424c45687472db803d87f79
- affected 11538d039ac6efcf4f1a6c536e1b87cd3668a9fd – < 24a6e55f17aa123bc1fc54b7d3c410b41bc16530
- affected 11538d039ac6efcf4f1a6c536e1b87cd3668a9fd – < a2241e62f6b4a774d8a92048fdf59c45f6c2fe5c
- affected 11538d039ac6efcf4f1a6c536e1b87cd3668a9fd – < fe0448a3fad365a747283a00a1d1ad5e8d6675b7
- affected 11538d039ac6efcf4f1a6c536e1b87cd3668a9fd – < abb02e05cb1c0a30dd873a29f33bc092067dc35d
- affected 11538d039ac6efcf4f1a6c536e1b87cd3668a9fd – < 58e2071742e38f29f051b709a5cca014ba51166f
- affected 4.11
- unaffected < 4.11
- unaffected 4.14.238 – ≤ 4.14.*
- unaffected 4.19.196 – ≤ 4.19.*
- unaffected 5.4.128 – ≤ 5.4.*
- unaffected 5.10.46 – ≤ 5.10.*
- unaffected 5.12.13 – ≤ 5.12.*
- unaffected 5.13 – ≤ *
References (6)
- https://git.kernel.org/stable/c/ad7feefe7164892db424c45687472db803d87f79 (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/24a6e55f17aa123bc1fc54b7d3c410b41bc16530 (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/a2241e62f6b4a774d8a92048fdf59c45f6c2fe5c (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/fe0448a3fad365a747283a00a1d1ad5e8d6675b7 (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/abb02e05cb1c0a30dd873a29f33bc092067dc35d (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/58e2071742e38f29f051b709a5cca014ba51166f (opens in a new tab)x_transferred
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)
- 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://trackcve.app/cve/CVE-2021-47223)Record last updated .