# CVE-2026-80890: sctp: reject stale cookies with mismatched verification tags


- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 4 Sep 2026
- **Updated:** 4 Sep 2026
- **Also known as:** AZL-99642, BELL-CVE-2026-80890, DEBIAN-CVE-2026-80890, GHSA-fqw8-ghgv-hjc2, UBUNTU-CVE-2026-80890

## What is CVE-2026-80890?

CVE-2026-80890 is a vulnerability in Linux, published on 4 Sep 2026. 

### Official description

In the Linux kernel, the following vulnerability has been resolved:

sctp: reject stale cookies with mismatched verification tags

sctp_unpack_cookie() skips cookie expiration checks whenever an
association already exists.  This is broader than the exception in
RFC 9260 Section 5.2.4.

For an existing association, Section 5.2.4 permits an expired State
Cookie only when both Verification Tags in the cookie match the current
association.  Otherwise, the packet SHOULD be discarded and a Stale
Cookie ERROR MUST be sent.

The broad check lets an expired Action A restart cookie reach
sctp_sf_do_dupcook_a().  In a runtime test with the default 60 second
cookie lifetime, replaying such a cookie after 65 seconds returned a
COOKIE-ACK and restarted the association.

Check cookie expiration unless both Verification Tags match.  This
preserves the Action D exception for a lost COOKIE ACK while rejecting
expired cookies in all other cases.

## Which versions are affected by CVE-2026-80890?


## How do I fix CVE-2026-80890?

Upgrade to a fixed version.

## Is CVE-2026-80890 being exploited?

There is no known exploitation of CVE-2026-80890 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80890 and fix it if it is affected.

What it is: CVE-2026-80890 is a vulnerability in Linux, published on 4 Sep 2026. 
Exploitation: There is no known exploitation of CVE-2026-80890 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-80890/ (Markdown: https://insights.sbomify.com/CVE-2026-80890/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80890
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80890
- OSV: https://osv.dev/vulnerability/CVE-2026-80890

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80890/
Summaries are generated and may contain mistakes; the official description above is the record.