# CVE-2026-72231: batman-adv: tt: avoid request storms during pending request

> A logic error in the batman-adv kernel module allows attackers to trigger request storms, causing denial of service.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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:** 16 Oct 2026
- **Also known as:** BELL-CVE-2026-72231, DEBIAN-CVE-2026-72231, GHSA-r9hr-vqwf-9q7r, UBUNTU-CVE-2026-72231

## What is CVE-2026-72231?

CVE-2026-72231 is a high-severity denial of service 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:

batman-adv: tt: avoid request storms during pending request

batadv_send_tt_request() allocates a tt_req_node when none exists for the
destination originator node. This should prevent that a multiple TT
requests are send at the same time to an originator.

But if allocation of the send buffer failed, this request must be cleaned
up again. But indicator for such a failure is "ret == false". But the
actual implementation is checking for "ret == true".

The check must be inverted to not loose the information about the TT
request directly after it was attempted to be sent out. This should avoid
potential request storms.

## Which versions are affected by CVE-2026-72231?


## How do I fix CVE-2026-72231?

Apply the vendor's patch.

## Is CVE-2026-72231 being exploited?

There is no known exploitation of CVE-2026-72231 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72231 and fix it if it is affected.

What it is: CVE-2026-72231 is a high-severity denial of service 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-2026-72231 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-2026-72231/ (Markdown: https://insights.sbomify.com/CVE-2026-72231/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72231
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72231
- OSV: https://osv.dev/vulnerability/CVE-2026-72231

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72231/
Summaries are generated and may contain mistakes; the official description above is the record.