# CVE-2024-56139: A stack overflow Segmentation Fault (SEGV) and Memory Leak in pdftools

> Maliciously crafted EPUB files cause a stack overflow and crash in pdftools, leading to denial of service.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 17 Dec 2024
- **Updated:** 20 Dec 2024

## What is CVE-2024-56139?

CVE-2024-56139 is a medium-severity denial of service vulnerability in leonhad pdftools, published on 17 Dec 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

pdftools is a high level tools to convert PDF files to ePUB formats. In versions up to and including 0.5.0 maliciously crafted epub files can cause a stack overflow leading to a crash. This issue has not yet been addressed and users are advised to avoid untrusted input to their systems.

Weakness: CWE-121 (Stack-based Buffer Overflow)

## Which versions are affected by CVE-2024-56139?


## How do I fix CVE-2024-56139?

No fix has been published for CVE-2024-56139 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-56139 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2024-56139 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-56139 and fix it if it is affected.

What it is: CVE-2024-56139 is a medium-severity denial of service vulnerability in leonhad pdftools, published on 17 Dec 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2024-56139 exists.

Affected product: leonhad pdftools. 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-2024-56139/ (Markdown: https://insights.sbomify.com/CVE-2024-56139/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-56139
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-56139
- OSV: https://osv.dev/vulnerability/CVE-2024-56139

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From sbomify Insights: https://insights.sbomify.com/CVE-2024-56139/
Summaries are generated and may contain mistakes; the official description above is the record.