# CVE-2026-72447: sctp: hold socket lock when dumping endpoints in sctp_diag

> A race condition in Linux kernel SCTP diagnostics allows local attackers to leak uninitialized memory to userspace.

- **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:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-72447, DEBIAN-CVE-2026-72447, GHSA-p5mf-mjh6-46fm, UBUNTU-CVE-2026-72447

## What is CVE-2026-72447?

CVE-2026-72447 is a vulnerability in Linux, published on 15 Aug 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:

sctp: hold socket lock when dumping endpoints in sctp_diag

SCTP_DIAG endpoint dumping was traversing endpoint address lists without
holding lock_sock(), while those lists could change concurrently via
socket operations (e.g., bindx changes). This creates a race where
nla_reserve() counts addresses under RCU protection, but the subsequent
copy may see fewer entries, potentially leaking uninitialized memory to
userspace.

Fix this by:

- Taking a reference on each endpoint during hash traversal
- Moving socket operations (lock_sock()) outside read_lock_bh()
- Serializing address list access during dump
- Reworking sctp_for_each_endpoint() to support restart-based traversal
  with (net, pos) tracking

Also:

- Add WARN_ON_ONCE() for inconsistent address counts
- Fix idiag_states filtering for LISTEN vs association cases
- Skip dumping endpoints being freed (ep->base.dead)
- Move dump position tracking into iterator, removing cb->args[4] and
  its comment for sctp_ep_dump().,
- Update the comment for cb->args[4] and remove the comment for unused
  cb->args[5] for sctp_sock_dump().

Note: traversal is restart-based and may re-scan buckets multiple times,
but this is acceptable due to small bucket sizes and required to support
sleeping-safe callbacks.

This issue was reported by Nico Yip (@_cyeaa_) working with TrendAI Zero
Day Initiative.

## Which versions are affected by CVE-2026-72447?


## How do I fix CVE-2026-72447?

Apply the vendor's patch.

## Is CVE-2026-72447 being exploited?

There is no known exploitation of CVE-2026-72447 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72447 and fix it if it is affected.

What it is: CVE-2026-72447 is a vulnerability in Linux, published on 15 Aug 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-2026-72447 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-2026-72447/ (Markdown: https://insights.sbomify.com/CVE-2026-72447/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72447
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72447
- OSV: https://osv.dev/vulnerability/CVE-2026-72447

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72447/
Summaries are generated and may contain mistakes; the official description above is the record.