What is CVE-2021-4017?

CVE-2021-4017 is a high-severity vulnerability in Showdoc, classified under Cross-Site Request Forgery (CSRF). CVSS score: 8.8/10. Published 2021-12-01.

How severe is CVE-2021-4017?

High severity. CVSS v3 base score is 8.8 out of 10.

Is CVE-2021-4017 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

CSRF in Showdoc

CVE-2021-4017

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 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.006 (47.4th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 47th percentile — 47.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: +0.000

Affected products

Showdoc
Star7th Star7th/showdoc — versions unspecified

Weakness classification (CWE)

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

Public proof-of-concept exploits

References

huntr.dev/bounties/1d8439e8-b3f7-40f8-8b30-f9cb05ff2bcd (Exploit, Patch, Third Party Advisory)
github.com/star7th/showdoc/commit/654e871a3923e79076818a9a03533fe88222c871 (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2021-4017?: CVE-2021-4017 is a high-severity vulnerability in Showdoc, classified under Cross-Site Request Forgery (CSRF). CVSS score: 8.8/10. Published 2021-12-01.
How severe is CVE-2021-4017?: High severity. CVSS v3 base score is 8.8 out of 10.
Is CVE-2021-4017 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.