CVE-2021-4000: showdoc is vulnerable to URL Redirection to Untrusted Site

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MEDIUM 6.1MITIGATE

CVE-2021-4000 is a medium-severity flaw (CVSS 6.1) affecting showdoc. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

showdoc is vulnerable to URL Redirection to Untrusted Site

Why this priority

Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.8% (top 42%)
CISA exploited list	No
Weakness	CWE-601
Published	2021-12-03
Last modified	2026-06-17

Publisher (CNA): huntr.dev · Vendor: showdoc

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-12-03 11:15 UTCPublished CVE record published
2026-06-17 04:18 UTCUpdated Record last modified

showdoc showdoc MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy showdoc || rpm -q showdoc || showdoc --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-4000?

showdoc: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-4000 being exploited?

CVE-2021-4000 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-4000 affect?

CVE-2021-4000 affects showdoc. Severity is medium (CVSS 6.1). showdoc is vulnerable to URL Redirection to Untrusted Site

How urgent is CVE-2021-4000?

Priority 41/100. Public exploit reference

Related CVEs

CVE-2022-1034 HIGH 7.2 UPGRADE There is a Unrestricted Upload of File vulnerability in ShowDoc v2.10.3 in GitHub repository star7th/showdoc p
CVE-2022-0967 MEDIUM 5.4 UPGRADE Stored XSS via File Upload in star7th/showdoc in star7th/showdoc in GitHub repository star7th/showdoc prior to
CVE-2022-0966 MEDIUM 5.4 UPGRADE Stored XSS via File Upload in star7th/showdoc in GitHub repository star7th/showdoc prior to 2.4.10.
CVE-2022-0965 MEDIUM 5.4 UPGRADE Stored XSS viva .ofd file upload in GitHub repository star7th/showdoc prior to 2.10.4.
CVE-2022-0964 MEDIUM 5.4 UPGRADE Stored XSS viva .webmv file upload in GitHub repository star7th/showdoc prior to 2.10.4.

References

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