# CVE-2026-80851: gtp: serialize PDP context updates

> A race condition in the Linux kernel GTP module allows concurrent PDP context deletions to cause a general protection fault and system crash.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 4 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-99569, BELL-CVE-2026-80851, DEBIAN-CVE-2026-80851, GHSA-wq34-548c-54v3, UBUNTU-CVE-2026-80851

## What is CVE-2026-80851?

CVE-2026-80851 is a vulnerability in Linux, published on 4 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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

gtp: serialize PDP context updates

PDP contexts can be deleted through GTP_CMD_DELPDP or while the GTP
network device is being unregistered. The latter is serialized by RTNL,
but the generic-netlink delete path only holds RCU.

Running both paths concurrently can therefore make both paths delete the
same PDP context. The issue was found through static analysis and
reproduced on a KASAN-enabled kernel by a simple two-thread program
racing GTP_CMD_DELPDP against RTM_DELLINK:

  Oops: general protection fault, probably for non-canonical address
  KASAN: maybe wild-memory-access in range
         [0xdead000000000120-0xdead000000000127]
  RIP: gtp_genl_del_pdp+0x1c1/0x420 [gtp]
  RBP: dead000000000122

The second deletion dereferenced the poisoned hlist pprev pointer.

Serialize gtp_pdp_add(), gtp_genl_del_pdp(), and gtp_dellink() with a
shared mutex. Keep the mutex held until the final use of a PDP context in
the NEWPDP path, and keep the RCU read-side section around the complete
PDP context use in the DELPDP path.

## Which versions are affected by CVE-2026-80851?


## How do I fix CVE-2026-80851?

Apply the vendor's patch.

## Is CVE-2026-80851 being exploited?

There is no known exploitation of CVE-2026-80851 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80851 and fix it if it is affected.

What it is: CVE-2026-80851 is a vulnerability in Linux, published on 4 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-80851 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-2026-80851/ (Markdown: https://insights.sbomify.com/CVE-2026-80851/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80851
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80851
- OSV: https://osv.dev/vulnerability/CVE-2026-80851

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80851/
Summaries are generated and may contain mistakes; the official description above is the record.