# CVE-2026-40505: MuPDF < 1.27 mutool ANSI Injection via Metadata

> Attackers can inject ANSI escape sequences via PDF metadata to manipulate terminal display in mutool, facilitating social engineering attacks.

- **Severity:** Medium 4.8 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 16 Apr 2026
- **Updated:** 14 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-40505, GHSA-hj44-m5xv-x75q, UBUNTU-CVE-2026-40505

## What is CVE-2026-40505?

CVE-2026-40505 is a medium-severity vulnerability in Artifex Mupdf, published on 16 Apr 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

MuPDF before 1.27 contains an ANSI injection vulnerability in mutool that allows attackers to inject arbitrary ANSI escape sequences through crafted PDF metadata fields. Attackers can embed malicious ANSI escape codes in PDF metadata that are passed unsanitized to terminal output when running mutool info, enabling them to manipulate terminal display for social engineering attacks such as presenting fake prompts or spoofed commands.

Weakness: CWE-150 (Improper Neutralization of Escape, Meta, or Control Sequences)

## Which versions are affected by CVE-2026-40505?

It affects 1 product.


Products: Artifex Mupdf.

## How do I fix CVE-2026-40505?

Upgrade to a fixed version.

## Is CVE-2026-40505 being exploited?

There is no known exploitation of CVE-2026-40505 in the wild and no public exploit code.

## 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-2026-40505 and fix it if it is affected.

What it is: CVE-2026-40505 is a medium-severity vulnerability in Artifex Mupdf, published on 16 Apr 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-40505 in the wild and no public exploit code.

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-2026-40505/ (Markdown: https://insights.sbomify.com/CVE-2026-40505/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40505
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40505
- OSV: https://osv.dev/vulnerability/CVE-2026-40505

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-40505/
Summaries are generated and may contain mistakes; the official description above is the record.