CVE-2026-46086
net: bridge: use a stable FDB dst snapshot in RCU readers
MEDIUM 5.5
At a glance
- Source
- NVD
- EPSS
- EPSS 0.13 % · percentile 2 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- Linux
- NVD status
- Undergoing Analysis
Description
In the Linux kernel, the following vulnerability has been resolved: net: bridge: use a stable FDB dst snapshot in RCU readers Local FDB entries can be rewritten in place by `fdb_delete_local()`, which updates `f->dst` to another port or to `NULL` while keeping the entry alive. Several bridge RCU readers inspect `f->dst`, including `br_fdb_fillbuf()` through the `brforward_read()` sysfs path. These readers currently load `f->dst` multiple times and can therefore observe inconsistent values across the check and later dereference. In `br_fdb_fillbuf()`, this means a concurrent local-FDB update can change `f->dst` after the NULL check and before the `port_no` dereference, leading to a NULL-ptr-deref. Fix this by taking a single `READ_ONCE()` snapshot of `f->dst` in each affected RCU reader and using that snapshot for the rest of the access sequence. Also publish the in-place `f->dst` updates in `fdb_delete_local()` with `WRITE_ONCE()` so the readers and writer use matching access patterns.
Weaknesses (CWE)
- CWE-476 — NULL Pointer Dereference
References
- https://git.kernel.org/stable/c/c502fa9f094cb03d1d1685c71e2105ab359bc2b8
- https://git.kernel.org/stable/c/a6ae4511c07b91f597e461406c6330f0d4ff810e
- https://git.kernel.org/stable/c/1406c4e0ed1eaf8a29801ab1163d00fb7ee4359a
- https://git.kernel.org/stable/c/0b9e4bbfb7c949151e3acd44ed4aa33614d2e110
- https://git.kernel.org/stable/c/81af4137a30c4c2dc694dea8cacb180bd66000ef
- https://git.kernel.org/stable/c/5424e678f9b304e148cf5dcc047cffc7a56a3bb5
- https://git.kernel.org/stable/c/9a2d9d4e657b23dc21f24cf139e3aeff0b61341f
- https://git.kernel.org/stable/c/df4601653201de21b487c3e7fffd464790cab808
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html
- https://cert-portal.siemens.com/productcert/html/ssa-784472.html
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H | NVD · nvd@nist.gov (Primary) |
European references
- ENISA EUVD · EUVD-2026-32469
- GCVE · GCVE-0-2026-46086
CERT-FR advisories
- CERTFR-2026-AVI-1385 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1333 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1298 — Multiples vulnérabilités dans les produits Siemens · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1286 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1094 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1066 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1064 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1029 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0955 — Multiples vulnérabilités dans le noyau Linux de Red Hat · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0954 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0927 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0926 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0899 — Multiples vulnérabilités dans le noyau Linux de Red Hat · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0862 — Multiples vulnérabilités dans le noyau Linux de Debian LTS · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0861 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0831 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0731 — Multiples vulnérabilités dans les produits Microsoft · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 3.14.1 < 5.10.259cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 5.11 < 5.15.210cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 5.16 < 6.1.176cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.2 < 6.6.140cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.7 < 6.12.86cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.13 < 6.18.27cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.19 < 7.0.4cpe:2.3:o:linux:linux_kernel:3.14:-:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:3.14:rc3:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:3.14:rc4:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:3.14:rc5:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:3.14:rc6:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:3.14:rc7:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:3.14:rc8:*:*:*:*:*:*
Affected products
| Product | Versions |
|---|---|
| Linux · Linux | affected 960b589f86c74ce582922fcb996103271081f4de < c502fa9f094cb03d1d1685c71e2105ab359bc2b8 ; affected 960b589f86c74ce582922fcb996103271081f4de < a6ae4511c07b91f597e461406c6330f0d4ff810e ; affected 960b589f86c74ce582922fcb996103271081f4de < 1406c4e0ed1eaf8a29801ab1163d00fb7ee4359a ; affected 960b589f86c74ce582922fcb996103271081f4de < 0b9e4bbfb7c949151e3acd44ed4aa33614d2e110 ; affected 960b589f86c74ce582922fcb996103271081f4de < 81af4137a30c4c2dc694dea8cacb180bd66000ef ; affected 960b589f86c74ce582922fcb996103271081f4de < 5424e678f9b304e148cf5dcc047cffc7a56a3bb5 |
| Linux · Linux | affected 3.14 ; unaffected 0 < 3.14 ; unaffected 5.10.259 ≤ 5.10.* ; unaffected 5.15.210 ≤ 5.15.* ; unaffected 6.1.176 ≤ 6.1.* ; unaffected 6.6.140 ≤ 6.6.* |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |