Is CVE-2021-34121 in the CISA KEV catalog?

No. CVE-2021-34121 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-34121?

CVE-2021-34121 has a CVSS v3 base score of 7.8 (HIGH).

What is the EPSS score for CVE-2021-34121?

CVE-2021-34121 has an EPSS score of 0.31% (23th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-34121?

Upgrade htmldoc on debian 12 to 1.9.13-1 or later. Fixes are available for 2 affected products.

CVE & CISA-KEV Catalog

CVE-2021-34121

HIGH

7.8

CVSS v3

NVD

Description

An Out of Bounds flaw was discovered in htmodoc 1.9.12 in function parse_tree() in toc.cxx, this possibly leads to memory layout information leaking in the data. This might be used in a chain of vulnerability in order to reach code execution.

CWE-125Out-of-bounds Read

How to fix

Remediation Available

htmldocDebian

Fixed in:1.9.13-1CVE-2021-34121

htmldocUbuntu

Fixed in:1.8.27-8ubuntu1+esm3USN-7189-1

Fixed in:1.8.27-8ubuntu1.1+esm2USN-7189-1

Fixed in:1.9.2-1ubuntu0.2+esm1USN-7189-1

Fixed in:1.9.7-1ubuntu0.3+esm1USN-7189-1

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityLow

Privileges RequiredNone

User InteractionRequired

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

0.31%probability of exploitation in 30 days

23rdpercentile

Low risk: more likely to be exploited than 23% of all known CVEs.

References

Patch1

github.com

Exploit1

github.com

Related Vulnerabilities

Other CWE-125 (Out-of-bounds Read) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2014-0160	High	7.5	100%	KEV	Fix
CVE-2025-5777	High	7.5	100%	KEV + Ransom	Fix
CVE-2021-4034	High	7.8	95%	KEV	Fix
CVE-2023-21769	High	7.5	92%	-	Fix
CVE-2023-49285	High	8.6	89%	-	Fix
CVE-2020-8794	Critical	9.8	89%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.