# CVE-2026-61632: PyMdown Extensions: Path traversal in the b64 extension lets <img src> read files outside base_path

> Attackers can read arbitrary image files outside the base directory by exploiting path traversal in the b64 extension of PyMdown Extensions.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 6 Aug 2026
- **Updated:** 7 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-61632, ECHO-d088-1f41-49db, GHSA-9xwg-3r6f-jcx2, PYSEC-2026-3609, UBUNTU-CVE-2026-61632

## What is CVE-2026-61632?

CVE-2026-61632 is a medium-severity path traversal vulnerability in facelessuser pymdown-extensions, published on 6 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

PyMdown Extensions is a set of extensions for the Python-Markdown markdown project. In versions up to and including 10.21.3, the b64 extension is vulnerable to a path traversal that discloses arbitrary files: it inlines images referenced by <img src="..."> by joining the src onto the configured base_path with os.path.normpath and opening the result directly, without verifying that the resolved path stays inside base_path. As a result, an src containing ../ sequences or an absolute path reads a file outside base_path as long as it has an allowed image extension (.png, .jpg, .jpeg, .gif, .svg), and the file's contents are then base64-encoded into the rendered output, disclosing them. An application that renders untrusted Markdown with pymdownx.b64 enabled can therefore leak the contents of image-extension files readable by the process to whoever controls the Markdown or views the output, a targeted file-read bounded by the extension check. This issue has been fixed in version 11.0.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-61632?

3 open source packages ship an affected version, including pymdown-extensions.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `pymdown-extensions` | PyPI | All versions | 11.0.0 |
| `pymdown-extensions` | PyPI | All versions | 11.0.0 |
| `pymdown-extensions` | PyPI | All versions | 11.0.0 |

## How do I fix CVE-2026-61632?

Upgrade pymdown-extensions to 11.0.0 or later.

## Is CVE-2026-61632 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-61632 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-61632 and fix it if it is affected.

What it is: CVE-2026-61632 is a medium-severity path traversal vulnerability in facelessuser pymdown-extensions, published on 6 Aug 2026. 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-2026-61632 exists.

Affected packages and fixed versions:
- pymdown-extensions (PyPI): affected all versions; fixed in 11.0.0
- pymdown-extensions (PyPI): affected all versions; fixed in 11.0.0
- pymdown-extensions (PyPI): affected all versions; fixed in 11.0.0

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-2026-61632/ (Markdown: https://insights.sbomify.com/CVE-2026-61632/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-61632
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-61632
- OSV: https://osv.dev/vulnerability/CVE-2026-61632

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-61632/
Summaries are generated and may contain mistakes; the official description above is the record.