# sctp: fix stream->outcnt underflow on duplicate RECONF responses

CVE record · `CVE-2026-89476`

- **Identifiers:** `CVE-2026-89476`
- **State:** Confirmed
- **Severity:** CVSS 7.5 High
- **Critical:** No
- **CNA:** Linux
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 11 Sept 2026
- **Updated:** 19 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 11 Sept 2026, 19:43 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: `11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 to before 041f7df5a929d3e7435dd8387e8ea17f2d412b7d` (git)
  - affected: `11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 to before 59f61c39cb99ee1737bd742a20094fe5653389bb` (git)
  - affected: `11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 to before 793519e343867ee9a3e84f6cac07f81f2aec7b5d` (git)
  - affected: `11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 to before 092acd3c55a4077b00489064615d8d2d898daf91` (git)
  - affected: `11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 to before 2d867663c563e8009257b9edf9c8ec75d9bbf19a` (git)
  - affected: `11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 to before d02a5794c3deedcb8476d017fcee2b7aaedab2e1` (git)
  - affected: `11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 to before 8320cbd81bc21a1ca6ebdf70ad610ebc5ef1bd68` (git)
  - affected: `11ae76e67a179f25ae8f772d62a7ddf717b1cdf3 to before 3faf13aff243ca9f78d08b1a2956ef5a6fc77b6e` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `4.12`
  - unaffected: `before 4.12` (semver)
  - unaffected: `5.10.270 to 5.10.*, inclusive` (semver)
  - unaffected: `5.15.221 to 5.15.*, inclusive` (semver)
  - unaffected: `6.1.188 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.157 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.109 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

## 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

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

- **CISA KEV:** Not listed.
- **EPSS:** 0.0070, the 53rd 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-2026-89476](https://www.cve.org/CVERecord?id=CVE-2026-89476)
- [NVD: CVE-2026-89476](https://nvd.nist.gov/vuln/detail/CVE-2026-89476)

### References from the CNA

- <https://git.kernel.org/stable/c/041f7df5a929d3e7435dd8387e8ea17f2d412b7d>
- <https://git.kernel.org/stable/c/59f61c39cb99ee1737bd742a20094fe5653389bb>
- <https://git.kernel.org/stable/c/793519e343867ee9a3e84f6cac07f81f2aec7b5d>
- <https://git.kernel.org/stable/c/092acd3c55a4077b00489064615d8d2d898daf91>
- <https://git.kernel.org/stable/c/2d867663c563e8009257b9edf9c8ec75d9bbf19a>
- <https://git.kernel.org/stable/c/d02a5794c3deedcb8476d017fcee2b7aaedab2e1>
- <https://git.kernel.org/stable/c/8320cbd81bc21a1ca6ebdf70ad610ebc5ef1bd68>
- <https://git.kernel.org/stable/c/3faf13aff243ca9f78d08b1a2956ef5a6fc77b6e>

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-2026-89476>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-89476/>. Everything for agents: <https://agentprime.io/llms.txt>.