# CVE-2026-9529: GNU LibreDWG Dwggrep Utility dwggrep.c match_BLOCK_HEADER null pointer dereference

> A local attacker can cause a denial of service via null pointer dereference in the Dwggrep utility of GNU LibreDWG.

- **Severity:** Medium 4.8 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P`)
- **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:** 26 May 2026
- **Updated:** 26 May 2026
- **Also known as:** GHSA-5ppw-fxgq-3w56

## What is CVE-2026-9529?

CVE-2026-9529 is a medium-severity vulnerability in GNU LibreDWG, published on 26 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A security flaw has been discovered in GNU LibreDWG up to 0.14. The affected element is the function match_BLOCK_HEADER of the file dwggrep.c of the component Dwggrep Utility. Performing a manipulation results in null pointer dereference. The attack requires a local approach. The exploit has been released to the public and may be used for attacks.

Weakness: CWE-476 (NULL Pointer Dereference), CWE-404 (Improper Resource Shutdown or Release)

## Which versions are affected by CVE-2026-9529?


## How do I fix CVE-2026-9529?

Upgrade to a fixed version.

## Is CVE-2026-9529 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-9529 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-9529 and fix it if it is affected.

What it is: CVE-2026-9529 is a medium-severity vulnerability in GNU LibreDWG, published on 26 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-9529 exists.

Affected product: GNU LibreDWG. 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-2026-9529/ (Markdown: https://insights.sbomify.com/CVE-2026-9529/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-9529
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-9529
- OSV: https://osv.dev/vulnerability/CVE-2026-9529

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-9529/
Summaries are generated and may contain mistakes; the official description above is the record.