# CVE-2026-112036: Artifex MuPDF Signature Locking pdf-xref.c free_char_list double free

> A double free vulnerability in MuPDF's signature locking allows remote attackers to cause denial of service or potentially execute code via crafted PDF files.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 19 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-112036, GHSA-pv37-v42r-g3rq, UBUNTU-CVE-2026-112036

## What is CVE-2026-112036?

CVE-2026-112036 is a medium-severity use after free vulnerability in Artifex MuPDF, published on 19 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

A vulnerability was detected in Artifex MuPDF up to 1.28.5. This impacts the function free_char_list of the file source/pdf/pdf-xref.c of the component Signature Locking. Performing a manipulation results in double free. The attack may be initiated remotely. The exploit is now public and may be used. The patch is named 3984925b660afb8a781ddf504021e91be1bc671e. To fix this issue, it is recommended to deploy a patch.

Weakness: CWE-415 (Double Free), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2026-112036?


## How do I fix CVE-2026-112036?

No fix has been published for CVE-2026-112036 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-112036 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-112036 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-112036 and fix it if it is affected.

What it is: CVE-2026-112036 is a medium-severity use after free vulnerability in Artifex MuPDF, published on 19 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-112036 exists.

Affected product: Artifex MuPDF. 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-2026-112036/ (Markdown: https://insights.sbomify.com/CVE-2026-112036/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-112036
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-112036
- OSV: https://osv.dev/vulnerability/CVE-2026-112036

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-112036/
Summaries are generated and may contain mistakes; the official description above is the record.