# CVE-2026-74752: sctp: validate cookie AUTH state before use

> A memory corruption vulnerability in the Linux kernel SCTP implementation allows local attackers to escalate privileges via forged cookie authentication data.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 26 Aug 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-97761, BELL-CVE-2026-74752, DEBIAN-CVE-2026-74752, GHSA-3494-mfxc-798j, UBUNTU-CVE-2026-74752

## What is CVE-2026-74752?

CVE-2026-74752 is a critical memory corruption vulnerability in Linux, published on 26 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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

sctp: validate cookie AUTH state before use

When cookie authentication is disabled, COOKIE_ECHO restores fixed-size
AUTH fields directly from peer-controlled cookie bytes.  A forged RANDOM
length, HMAC list, or CHUNKS list can then reach association consumers
with lengths or identifiers that were never validated against the local
backing arrays.

A forged RANDOM length can cause out-of-bounds reads during key-vector
construction.  A forged HMAC identifier also caused a 32-byte write past
a zero-length AUTH chunk, providing a primitive for a local privilege
escalation chain.

Validate the cookie's RANDOM, HMACS, and CHUNKS parameters at the cookie
trust boundary before copying them into the association.  Reject invalid
types, malformed lengths, unsupported HMAC identifiers, HMAC lists
without SHA1, and forbidden chunk ids.

## Which versions are affected by CVE-2026-74752?


## How do I fix CVE-2026-74752?

Apply the vendor's patch.

## Is CVE-2026-74752 being exploited?

There is no known exploitation of CVE-2026-74752 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74752 and fix it if it is affected.

What it is: CVE-2026-74752 is a critical memory corruption vulnerability in Linux, published on 26 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-74752 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-2026-74752/ (Markdown: https://insights.sbomify.com/CVE-2026-74752/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74752
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74752
- OSV: https://osv.dev/vulnerability/CVE-2026-74752

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74752/
Summaries are generated and may contain mistakes; the official description above is the record.