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.

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

EPSS: 0.007 (49.0th percentile) — read the EPSS interpretation.

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.

Affected products

Opencats — versions 0

Weakness classification (CWE)

CWE-306 — Missing Authentication for Critical Function

References

disclosure@vulncheck.com (exploit)
disclosure@vulncheck.com (product)
disclosure@vulncheck.com (product)
disclosure@vulncheck.com (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.