# CVE-2026-25556: MuPDF 1.23.0 through 1.27.0 Barcode Decoding Double Free

> A double-free vulnerability in MuPDF's barcode decoding allows attackers to crash the application or potentially execute code via crafted input.

- **Severity:** Medium 5.9 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **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:** Yes
- **Published:** 6 Feb 2026
- **Updated:** 14 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-25556, GHSA-39p9-g2pq-q8r7, UBUNTU-CVE-2026-25556

## What is CVE-2026-25556?

CVE-2026-25556 is a medium-severity use after free vulnerability in Artifex Mupdf, published on 6 Feb 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

MuPDF versions 1.23.0 through 1.27.0 contain a double-free vulnerability in fz_fill_pixmap_from_display_list() when an exception occurs during display list rendering. The function accepts a caller-owned fz_pixmap pointer but incorrectly drops the pixmap in its error handling path before rethrowing the exception. Callers (including the barcode decoding path in fz_decode_barcode_from_display_list) also drop the same pixmap in cleanup, resulting in a double-free that can corrupt the heap and crash the process. This issue affects applications that enable and use MuPDF barcode decoding and can be triggered by processing crafted input that causes a rendering-time error while decoding barcodes.

Weakness: CWE-415 (Double Free)

## Which versions are affected by CVE-2026-25556?

It affects 1 product.


Products: Artifex Mupdf.

## How do I fix CVE-2026-25556?

Apply the vendor's patch.

## Is CVE-2026-25556 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-25556 exists.

## Other vulnerabilities in Artifex Mupdf

- [CVE-2019-7321](https://insights.sbomify.com/CVE-2019-7321/): Memory corruption in n/a (critical 9.8)
- [CVE-2016-6525](https://insights.sbomify.com/CVE-2016-6525/): Memory corruption in n/a (critical 9.8)
- [CVE-2011-0341](https://insights.sbomify.com/CVE-2011-0341/): Memory corruption in n/a (critical 9.3)
- [CVE-2016-8728](https://insights.sbomify.com/CVE-2016-8728/): Memory corruption in MuPDF (high 8.6)
- [CVE-2021-3407](https://insights.sbomify.com/CVE-2021-3407/): Use after free in mupdf (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-25556 and fix it if it is affected.

What it is: CVE-2026-25556 is a medium-severity use after free vulnerability in Artifex Mupdf, published on 6 Feb 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-2026-25556 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-2026-25556/ (Markdown: https://insights.sbomify.com/CVE-2026-25556/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-25556
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-25556
- OSV: https://osv.dev/vulnerability/CVE-2026-25556

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-25556/
Summaries are generated and may contain mistakes; the official description above is the record.