Upsonic is vulnerable to Path Traversal attack through its os.path.join function

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

2.0 · CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X · score source

EPSS

• CVE-2025-6278: 0.70% estimated exploitation activity in the next 30 days; percentile 53.29 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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.

Published by the source

19 Jun 2025, 21:31 UTC

Last modified by the source

9 Jul 2025, 01:42 UTC

Source last checked

26 Oct 2026, 13:32 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-8jf4-fcjr-68c2

2. Revision 2 · amended · 25 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-8jf4-fcjr-68c2

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# Patch Next advisory brief: CVE-2025-6278

Advisory: Upsonic is vulnerable to Path Traversal attack through its os.path.join function
IDs: CVE-2025-6278, GHSA-8jf4-fcjr-68c2
Record: https://patchnext.com/advisories/cve-2025-6278 (revision 3, source checked 26 Oct 2026, 13:32 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 2.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: upsonic 0.56.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI upsonic: affected < 0.56.0; fixed in 0.56.0

## Suggested inspection (read-only)
- `python -m pip show upsonic`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on upsonic.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-8jf4-fcjr-68c2 (OSV record GHSA-8jf4-fcjr-68c2 lists affected ranges: PyPI upsonic >=0 <0.56.0 (fixed))
- Verified: https://github.com/advisories/GHSA-8jf4-fcjr-68c2 (GitHub-reviewed advisory GHSA-8jf4-fcjr-68c2 lists affected ranges: PyPI upsonic >=0 <0.56.0)

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