# CVE-2026-72220: sunrpc: harden rq_procinfo lifecycle to prevent double-free

> A double-free or use-after-free in the Linux kernel's sunrpc module allows attackers to potentially execute code or escalate privileges via crafted RPC requests.

- **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:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-72220, DEBIAN-CVE-2026-72220, GHSA-m4wq-7wv4-xpq8, UBUNTU-CVE-2026-72220

## What is CVE-2026-72220?

CVE-2026-72220 is a critical use after free vulnerability in Linux, published on 15 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:

sunrpc: harden rq_procinfo lifecycle to prevent double-free

The svc_release_rqst() function executes the callback inside
rqstp->rq_procinfo->pc_release. However, if a worker thread begins
processing a new request and encounters an early error path (e.g.,
unsupported protocol, short frame, or bad auth) before a valid
rq_procinfo is installed, a stale release hook can be re-triggered
against reused state from the previous RPC, resulting in a double-free
or use-after-free vulnerability.

Harden the lifecycle of rq_procinfo by:
1. Ensuring svc_release_rqst() always clears rq_procinfo after the
   optional pc_release() call, regardless of whether the hook exists.
2. Explicitly clearing rq_procinfo at request entry in svc_process()
   before any early decode or drop paths.
3. Ensuring svc_process_bc() does the same at backchannel entry.

This guarantees that error flows will not encounter a non-NULL stale
rq_procinfo pointer when there is nothing to release.

## Which versions are affected by CVE-2026-72220?


## How do I fix CVE-2026-72220?

Apply the vendor's patch.

## Is CVE-2026-72220 being exploited?

There is no known exploitation of CVE-2026-72220 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72220 and fix it if it is affected.

What it is: CVE-2026-72220 is a critical use after free vulnerability in Linux, published on 15 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-2026-72220 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-2026-72220/ (Markdown: https://insights.sbomify.com/CVE-2026-72220/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72220
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72220
- OSV: https://osv.dev/vulnerability/CVE-2026-72220

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72220/
Summaries are generated and may contain mistakes; the official description above is the record.