# net: bridge: mcast: fix use-after-free of a master VLAN's multicast context

CVE record · `CVE-2026-80842`

- **Identifiers:** `CVE-2026-80842`
- **State:** Confirmed
- **Severity:** No CVSS score
- **Critical:** No
- **CNA:** Linux
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 4 Sept 2026
- **Updated:** 19 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 4 Sept 2026, 15:54 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

## Affected products, as the CNA wrote them

- Vendor: Linux. Product: Linux.
  - affected: `7b54aaaf53cb784411426c64482af0435f7c845e to before 3afaaee2f972aec9059110953adb62fa3cf5c4bd` (git)
  - affected: `7b54aaaf53cb784411426c64482af0435f7c845e to before 22226a2c3b90f15b0925f1464470d3baa6c5677e` (git)
  - affected: `7b54aaaf53cb784411426c64482af0435f7c845e to before 7c54fd8cfbcf371a5ef50db5c53fe6e85fb76686` (git)
  - affected: `7b54aaaf53cb784411426c64482af0435f7c845e to before 3a0ad4fcdfa0b7dba1876de14a12cb65c8b5ca50` (git)
  - affected: `7b54aaaf53cb784411426c64482af0435f7c845e to before c069f29da72324697aa4b7cab5b3647a7d24a575` (git)
  - affected: `7b54aaaf53cb784411426c64482af0435f7c845e to before 3f4752996735e0628af559aa8da1d872c2fac13b` (git)
  - affected: `7b54aaaf53cb784411426c64482af0435f7c845e to before 57f94d3f4dee8b54d63cefddf1112be4656ef9e6` (git)
  - affected: `7b54aaaf53cb784411426c64482af0435f7c845e to before 50e5c6605cc9c2dd57bd2d1b3459674d19738983` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `5.15`
  - unaffected: `before 5.15` (semver)
  - unaffected: `5.15.220 to 5.15.*, inclusive` (semver)
  - unaffected: `6.1.187 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.156 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.108 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.49 to 6.18.*, inclusive` (semver)
  - unaffected: `7.1.13 to 7.1.*, inclusive` (semver)
  - unaffected: `7.2.3 to 7.2.*, inclusive` (semver)
  - unaffected: `7.3 to *, inclusive` (original_commit_for_fix)
  - Other versions: affected

## Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

## Severity and exploitation

No source has published a CVSS score for this record yet.

- **CISA KEV:** Not listed.
- **EPSS:** 0.0018, the 7th percentile, on 14 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the CVE Program, published 4 Sept 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-80842](https://www.cve.org/CVERecord?id=CVE-2026-80842)
- [NVD: CVE-2026-80842](https://nvd.nist.gov/vuln/detail/CVE-2026-80842)

### References from the CNA

- <https://git.kernel.org/stable/c/3afaaee2f972aec9059110953adb62fa3cf5c4bd>
- <https://git.kernel.org/stable/c/22226a2c3b90f15b0925f1464470d3baa6c5677e>
- <https://git.kernel.org/stable/c/7c54fd8cfbcf371a5ef50db5c53fe6e85fb76686>
- <https://git.kernel.org/stable/c/3a0ad4fcdfa0b7dba1876de14a12cb65c8b5ca50>
- <https://git.kernel.org/stable/c/c069f29da72324697aa4b7cab5b3647a7d24a575>
- <https://git.kernel.org/stable/c/3f4752996735e0628af559aa8da1d872c2fac13b>
- <https://git.kernel.org/stable/c/57f94d3f4dee8b54d63cefddf1112be4656ef9e6>
- <https://git.kernel.org/stable/c/50e5c6605cc9c2dd57bd2d1b3459674d19738983>

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.

## Check whether this affects you

This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it. Compare the affected versions above with what you run.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), `get_advisory` returns this record and `search_advisories` finds related ones. Setup: <https://agentprime.io/mcp.md>
- As JSON: <https://api.agentprime.io/v1/advisories/CVE-2026-80842>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-80842/>. Everything for agents: <https://agentprime.io/llms.txt>.