CVE-2026-109153 MosaicML Composer Checkpoint Extraction checkpoint.py tarball.extractall path traversal
Remote attackers can exploit path traversal in MosaicML Composer checkpoint extraction to read or modify arbitrary files.
- 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
- None listed
What is CVE-2026-109153?
CVE-2026-109153 is a medium-severity path traversal vulnerability in MosaicML Composer, published on 13 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 MosaicML Composer up to 0.32.1. This affects the function tarball.extractall of the file composer/utils/checkpoint.py of the component Checkpoint Extraction. The manipulation results in path traversal. The attack can be executed remotely. The vendor was contacted early about this disclosure.
Weakness: CWE-22
Which versions are affected by CVE-2026-109153?
How do I fix CVE-2026-109153?
No fix has been published for CVE-2026-109153 yet. Limit exposure of the affected software until one is available.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-109153 being exploited?
There is no known exploitation of CVE-2026-109153 in the wild and no public exploit code.
Sources
Also known as GHSA-9h32-g52h-pxjh.