# ip: orphan prefetched skbs before multicast forwarding

CVE record · `CVE-2026-89564`

- **Identifiers:** `CVE-2026-89564`
- **State:** Confirmed
- **Severity:** CVSS 7.8 High
- **Critical:** No
- **CNA:** Linux
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 11 Sept 2026
- **Updated:** 30 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 11 Sept 2026, 19:44 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: `cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449 to before 592b91f41d4f35e37c9e0be1c46a4c28437642cd` (git)
  - affected: `cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449 to before 882212d317a7c16ab70d20656f6b1c42abada9f6` (git)
  - affected: `cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449 to before e62aef7d6a5b27569bf540bbe11a9482117ff588` (git)
  - affected: `cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449 to before a8af6fbac895f057c4b8ff8a2e3fb4c5827fe4ce` (git)
  - affected: `cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449 to before f1281d4b99089fbaf0d3579bba62a814ebb4de4d` (git)
  - affected: `cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449 to before e36ce6e78fe3fc3c071a26750783b7ba081ce10d` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `5.7`
  - unaffected: `before 5.7` (semver)
  - unaffected: `6.1.191 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.160 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.111 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.50 to 6.18.*, inclusive` (semver)
  - unaffected: `7.2.4 to 7.2.*, inclusive` (semver)
  - unaffected: `7.3 to *, inclusive` (original_commit_for_fix)
  - Other versions: affected

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Linux kernel IPv4 and IPv6 multicast forwarding can dereference a stale socket pointer after the socket is destroyed, affecting versions from 5.7 until fixed. The source gives few details on what an attacker needs. Upgrade to 6.1.191, 6.6.160, 6.12.111, 6.18.50, or a later release in those branches.

Written 12 Nov 2026.

## 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

- 7.8 High, CVSS 3.1: `CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`, from CNA (Linux)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0014, the 3rd 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 11 Sept 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-89564](https://www.cve.org/CVERecord?id=CVE-2026-89564)
- [NVD: CVE-2026-89564](https://nvd.nist.gov/vuln/detail/CVE-2026-89564)

### References from the CNA

- <https://git.kernel.org/stable/c/592b91f41d4f35e37c9e0be1c46a4c28437642cd>
- <https://git.kernel.org/stable/c/882212d317a7c16ab70d20656f6b1c42abada9f6>
- <https://git.kernel.org/stable/c/e62aef7d6a5b27569bf540bbe11a9482117ff588>
- <https://git.kernel.org/stable/c/a8af6fbac895f057c4b8ff8a2e3fb4c5827fe4ce>
- <https://git.kernel.org/stable/c/f1281d4b99089fbaf0d3579bba62a814ebb4de4d>
- <https://git.kernel.org/stable/c/e36ce6e78fe3fc3c071a26750783b7ba081ce10d>

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-2026-89564>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-89564/>. Everything for agents: <https://agentprime.io/llms.txt>.