What is CVE-2021-3993?

CVE-2021-3993 is a medium-severity vulnerability in Showdoc, classified under Cross-Site Request Forgery (CSRF). CVSS score: 6.5/10. Published 2021-12-01.

How severe is CVE-2021-3993?

Medium severity. CVSS v3 base score is 6.5 out of 10.

CSRF in Showdoc

CVE-2021-3993

showdoc is vulnerable to Cross-Site Request Forgery (CSRF)

Vulnerability class: CSRF (Cross-Site Request Forgery)

Published 2021-12-01 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N.

EPSS exploit prediction

EPSS: 0.005 (42.0th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 42nd percentile — 42.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: +0.000

Affected products

Showdoc
Star7th Star7th/showdoc — versions unspecified

Weakness classification (CWE)

CWE-352 — Cross-Site Request Forgery (CSRF)

References

github.com/star7th/showdoc/commit/654e871a3923e79076818a9a03533fe88222c871 (Patch, Third Party Advisory)
huntr.dev/bounties/0aa84736-139b-4ae7-becf-604f7f60b1c9 (Exploit, Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2021-3993?: CVE-2021-3993 is a medium-severity vulnerability in Showdoc, classified under Cross-Site Request Forgery (CSRF). CVSS score: 6.5/10. Published 2021-12-01.
How severe is CVE-2021-3993?: Medium severity. CVSS v3 base score is 6.5 out of 10.