How severe is CVE-2021-23165?

CVE-2021-23165 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-23165 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (87th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-23165?

CVE-2021-23165 affects Htmldoc Project Htmldoc. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-23165?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-23165 published?

CVE-2021-23165 was published on 2022-03-16 and last updated on 2026-06-17.

CVE-2021-23165

CVE-2021-23165 is a critical-severity vulnerability in Htmldoc Project Htmldoc with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 10.0
EPSS exploit prediction: 3% (87th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Htmldoc Project Htmldoc
Published: 2022-03-16
Last modified: 2026-06-17

Description

A flaw was found in htmldoc before v1.9.12. Heap buffer overflow in pspdf_prepare_outpages(), in ps-pdf.cxx may lead to execute arbitrary code and denial of service.

Frequently asked questions

What is CVE-2021-23165?: A flaw was found in htmldoc before v1.9.12. Heap buffer overflow in pspdf_prepare_outpages(), in ps-pdf.cxx may lead to execute arbitrary code and denial of service.
How severe is CVE-2021-23165?: CVE-2021-23165 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-23165 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (87th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-23165?: CVE-2021-23165 affects Htmldoc Project Htmldoc. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-23165?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-23165 published?: CVE-2021-23165 was published on 2022-03-16 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:htmldoc_project:htmldoc:*:*:*:*:*:*:*:*

More vulnerabilities in Htmldoc Project Htmldoc

CVE-2024-46478 — Critical (CVSS 9.8): HTMLDOC v1.9.18 contains a buffer overflow in parse_pre function,ps-pdf.cxx:5681.
CVE-2024-45508 — Critical (CVSS 9.8): HTMLDOC before 1.9.19 has an out-of-bounds write in parse_paragraph in ps-pdf.cxx because of an attempt to strip…
CVE-2021-23158 — Critical (CVSS 9.8): A flaw was found in htmldoc in v1.9.12. Double-free in function pspdf_export(),in ps-pdf.cxx may result in a…
CVE-2021-20308 — Critical (CVSS 9.8): Integer overflow in the htmldoc 1.9.11 and before may allow attackers to execute arbitrary code and cause a denial of…
CVE-2021-34121 — High (CVSS 7.8): An Out of Bounds flaw was discovered in htmodoc 1.9.12 in function parse_tree() in toc.cxx, this possibly leads to…
CVE-2021-34119 — High (CVSS 7.8): A flaw was discovered in htmodoc 1.9.12 in function parse_paragraph in ps-pdf.cxx ,this flaw possibly allows possible…

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