CVE-2025-6278 Upsonic server.py os.path.join path traversal
Attackers can exploit path traversal in Upsonic's server to read or modify arbitrary files on the host system.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-6278?
CVE-2025-6278 is a medium-severity path traversal vulnerability in Upsonic, published on 19 Jun 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A vulnerability classified as critical was found in Upsonic up to 0.55.6. This vulnerability affects the function os.path.join of the file markdown/server.py. The manipulation of the argument file.filename leads to path traversal. The exploit has been disclosed to the public and may be used.
Weakness: CWE-22
Which versions are affected by CVE-2025-6278?
3 open source packages ship an affected version, including upsonic. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
upsonic PyPI | All versions | 0.56.0 |
upsonic PyPI | All versions | 0.56.0 |
upsonic PyPI | All versions | 0.56.0 |
Products include Upsonic Upsonic.
How do I fix CVE-2025-6278?
Upgrade upsonic to 0.56.0 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2025-6278 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-6278 exists.
Other vulnerabilities in Upsonic
Sources
Also known as GHSA-8jf4-fcjr-68c2, PYSEC-2025-67.