How severe is CVE-2025-6278?

No CVSS score has been assigned to CVE-2025-6278 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2025-6278?

CVE-2025-6278 affects the following packages: upsonic (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2025-6278?

Update upsonic to 0.56.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-6278 is resolved across your whole dependency graph.

How do I detect CVE-2025-6278 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for upsonic, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2025-6278 if there is no patch (or I can't update yet)?

Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Is CVE-2025-6278 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-6278 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-6278?

CVE-2025-6278 has an EPSS (Exploit Prediction Scoring System) score of 0.7%, placing it in the 53th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2025-6278?

CVE-2025-6278 is classified as Path Traversal (CWE-22). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2025-6278 published, and has it been updated?

CVE-2025-6278 was published on June 19, 2025 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

CVE-2025-6278 — upsonic

Fix: Upsonic/Upsonic#360

CVE-2025-6278 is a Path Traversal vulnerability in upsonic. A fix is available for upsonic — see the affected versions and patch details below.

Upsonic server.py os.path.join path traversal

Also known asGHSA-8jf4-fcjr-68c2PYSEC-2025-67

Published

Jun 19, 2025

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 31, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.

Exploitation and automatability from CISA’s SSVC triage for CVE-2025-6278.

EPSS Exploitation Probability

via FIRST.org ↗

0.7%probability of exploitation in next 30 days

Lower Risk-0.08%

Lower risk than most CVEs53th percentile — riskier than 53% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐍upsonic

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

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.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`upsonic`	all versions	0.56.0`pip install --upgrade 'upsonic==0.56.0'`

Affected Products

1 product · 1 configurations

Application

upsonicupsonic

≤ 0.55.6

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for upsonic, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update upsonic to 0.56.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-6278 is resolved across your whole dependency graph.
Workarounds
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

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