# CVE-2026-99056: strparser: make sure __strp_recv isn't running before tearing down the parser


- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 23 Oct 2026
- **Updated:** 24 Oct 2026
- **Also known as:** AZL-110939, BELL-CVE-2026-99056, DEBIAN-CVE-2026-99056, GHSA-cxj6-cg32-r3fc, UBUNTU-CVE-2026-99056

## What is CVE-2026-99056?

CVE-2026-99056 is a high-severity vulnerability in Linux, published on 23 Oct 2026. 

### Official description

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

strparser: make sure __strp_recv isn't running before tearing down the parser

The comment above strp_done() claims that if strp is stopped,
strp_recv will no longer be called. That's only true if the caller has
a mechanism (eg locking) to guarantee that strp_recv() calls that
started before strp_stop() have completed by the time we call
strp_done().

This adds a dummy lock_sock/release_sock pair to guarantee that any
in-flight strp_recv() (which runs under either bh_lock_sock or
lock_sock, depending if it's called from ->sk_data_ready or strp_work)
has completed.

Only espintcp can be affected by this race condition, but this patch
makes sure no future user of strp can have the bug.

This could crash on strp->sk ("general mode" of strp), but this mode
has been here for 9 years and has never been used. It'll be gone soon,
no point worrying about it.

Switch the stopped/paused/etc bits to u8's to avoid races between
strp_stop() and strp_pause/unpause().

A reproducer has been published and turns the possible UAF into an
exploit [1].

## Which versions are affected by CVE-2026-99056?


## How do I fix CVE-2026-99056?

Upgrade to a fixed version.

## Is CVE-2026-99056 being exploited?

There is no known exploitation of CVE-2026-99056 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-99056 and fix it if it is affected.

What it is: CVE-2026-99056 is a high-severity vulnerability in Linux, published on 23 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-99056 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-2026-99056/ (Markdown: https://insights.sbomify.com/CVE-2026-99056/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-99056
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-99056
- OSV: https://osv.dev/vulnerability/CVE-2026-99056

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-99056/
Summaries are generated and may contain mistakes; the official description above is the record.