# CVE-2026-68376: sctp: fix auth_hmacs array size in struct sctp_cookie

> A buffer overflow in the Linux kernel SCTP implementation allows attackers to corrupt memory, potentially leading to code execution or system crashes.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/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:** 10 Aug 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-68376, DEBIAN-CVE-2026-68376, GHSA-55hr-9mvf-6m8f, UBUNTU-CVE-2026-68376

## What is CVE-2026-68376?

CVE-2026-68376 is a high-severity memory corruption vulnerability in Linux, published on 10 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: fix auth_hmacs array size in struct sctp_cookie

The auth_hmacs array in struct sctp_cookie is supposed to store a complete
SCTP_AUTH_HMAC_ALGO parameter, which consists of a struct sctp_paramhdr
followed by N HMAC identifiers.

However, the array size was calculated using an extra 2 bytes instead of
sizeof(struct sctp_paramhdr), which is 4 bytes. When four HMAC identifiers
are configured, the HMAC-ALGO parameter stored in the endpoint is larger
than the auth_hmacs buffer in the cookie.

As a result, sctp_association_init() copies beyond the end of auth_hmacs
when initializing the association, corrupting the adjacent auth_chunks
field. This can lead to an invalid HMAC identifier being accepted and later
cause an out-of-bounds read in sctp_auth_get_hmac().

Fix the array size calculation by including the full SCTP parameter header
size.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-68376?


## How do I fix CVE-2026-68376?

Apply the vendor's patch.

## Is CVE-2026-68376 being exploited?

There is no known exploitation of CVE-2026-68376 in the wild and no public exploit code.

Public exploit code:

- CVE-2026-68376 - Ubuntu Kernel 7.0.0-30 (github_poc): https://github.com/gagaltotal/CVE-2026-68376-Ubuntu-7.0.0-30-Poc

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68376 and fix it if it is affected.

What it is: CVE-2026-68376 is a high-severity memory corruption vulnerability in Linux, published on 10 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-2026-68376 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-2026-68376/ (Markdown: https://insights.sbomify.com/CVE-2026-68376/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68376
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68376
- OSV: https://osv.dev/vulnerability/CVE-2026-68376

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68376/
Summaries are generated and may contain mistakes; the official description above is the record.