Auth bypass in Opencats
CVE-2021-47936
OpenCATS 0.9.4 contains a remote code execution vulnerability that allows unauthenticated attackers to execute arbitrary commands by uploading malicious PHP files disguised as resume attachments. Attackers can upload PHP payloads through the careers job application endpoint and execute system commands via POST requests to the uploaded file in the upload directory.
Vulnerability class: Broken Authentication
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.007 (50.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 50th percentile — 50.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000
Affected products
- Opencats — versions 0
Weakness classification (CWE)
References
- www.exploit-db.com/exploits/50585 (exploit)
- www.opencats.org/ (product)
- github.com/opencats/OpenCATS (product)
- www.vulncheck.com/advisories/opencats-remote-code-execution-via-resume-upload (third-party-advisory)
Frequently asked questions
- What is CVE-2021-47936?
- CVE-2021-47936 is a critical-severity vulnerability in Opencats, classified under Missing Authentication for Critical Function. CVSS score: 9.8/10. Published 2026-05-10.
- How severe is CVE-2021-47936?
- Critical severity. CVSS v3 base score is 9.8 out of 10.