CVE-2021-20308

Name: CVE-2021-20308
Creator: NVD / NIST
Published: 2021-04-05T22:15:12.947+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 2.48%

Last modified Jun 17, 2026

CVE-2021-20308 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. Integer overflow in the htmldoc 1.9.11 and before may allow attackers to execute arbitrary code and cause a denial of service that is similar to CVE-2017-9181.. EPSS estimates a 2.48% chance of exploitation in the next 30 days.

Description

Integer overflow in the htmldoc 1.9.11 and before may allow attackers to execute arbitrary code and cause a denial of service that is similar to CVE-2017-9181.

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

2.48%

82.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-190

Affected Software

Vendor	Product	Versions
Htmldoc Project	Htmldoc	<= 1.9.11
Debian	Debian Linux	9.0

References

https://bugzilla.redhat.com/show_bug.cgi?id=1946289Exploit, Issue Tracking, Third Party Advisory
https://github.com/michaelrsweet/htmldoc/issues/423Exploit, Issue Tracking, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/07/msg00000.htmlMailing List, Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1946289Exploit, Issue Tracking, Third Party Advisory
https://github.com/michaelrsweet/htmldoc/issues/423Exploit, Issue Tracking, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/07/msg00000.htmlMailing List, Third Party Advisory

Timeline

Published: Apr 5, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-20308?

Integer overflow in the htmldoc 1.9.11 and before may allow attackers to execute arbitrary code and cause a denial of service that is similar to CVE-2017-9181.

How severe is CVE-2021-20308?

CVE-2021-20308 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 2.48% probability of exploitation in the next 30 days.

How do I fix CVE-2021-20308?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-20308?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST