# CVE-2026-9501: GNU LibreDWG Dwgread Utility decode.c decompress_R2004_section assertion

> A local attacker can trigger a reachable assertion in the Dwgread utility, causing a denial of service.

- **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:** 25 May 2026
- **Updated:** 28 May 2026
- **Also known as:** GHSA-f6gf-3cj7-46vv

## What is CVE-2026-9501?

CVE-2026-9501 is a medium-severity denial of service vulnerability in GNU LibreDWG, published on 25 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A vulnerability was determined in GNU LibreDWG up to 0.14. The impacted element is the function decompress_R2004_section of the file src/decode.c of the component Dwgread Utility. Executing a manipulation can lead to reachable assertion. The attack is restricted to local execution. The exploit has been publicly disclosed and may be utilized. This patch is called e501cb9926c1e9a07a0d1cc997f3e69e9be801c9. A patch should be applied to remediate this issue.

Weakness: CWE-617 (Reachable Assertion)

## Which versions are affected by CVE-2026-9501?


## How do I fix CVE-2026-9501?

Apply the vendor's patch.

## Is CVE-2026-9501 being exploited?

There is no known exploitation of CVE-2026-9501 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-9501 and fix it if it is affected.

What it is: CVE-2026-9501 is a medium-severity denial of service vulnerability in GNU LibreDWG, published on 25 May 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-2026-9501 in the wild and no public exploit code.

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-2026-9501/ (Markdown: https://insights.sbomify.com/CVE-2026-9501/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-9501
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-9501
- OSV: https://osv.dev/vulnerability/CVE-2026-9501

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-9501/
Summaries are generated and may contain mistakes; the official description above is the record.