CVE-2021-23165

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-03-17. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 4%CVSS: 9.8Exploit: None knownExposed: 0

A fix is available — apply it.

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.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
50(Track)
EG Risk 50/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation3% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
4%
EPSS %ILE
88%
KEV
Not listed

Published

March 16, 2022

Last Modified

February 5, 2025

Advisory Details (4)

Auto-updated Sep 4, 2026
Upstream fix merged — awaiting tagged release. Sources: redhat, github_commit.
generic

AddressSanitizer: heap-buffer-overflow in pspdf_prepare_outpages() in ps-pdf.cxx:1338:15 · Issue #413 · michaelrsweet/htmldoc · GitHub

https://github.com/michaelrsweet/htmldoc/issues/413
generic
https://github.com/michaelrsweet/htmldoc/commit/6e8a95561988500b5b5ae4861b3b0cbf4fba517f.patch
github_commit

commit 6e8a95561988 (michaelrsweet/htmldoc)

Fix landed in michaelrsweet/htmldoc commit 6e8a95561988 — awaiting tagged release

https://github.com/michaelrsweet/htmldoc/commit/6e8a95561988500b5b5ae4861b3b0cbf4fba517f
redhat

1967014 – (CVE-2021-23165) CVE-2021-23165 htmldoc: heap-buffer-overflow in pspdf_prepare_outpages()

https://bugzilla.redhat.com/show_bug.cgi?id=1967014

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuhtmldoc-common (1.9.7-1ubuntu0.3) @ focal2026-05-26ubuntu
ubuntuhtmldoc-common (1.8.27-8ubuntu1.1+esm1) @ xenial2026-05-26ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(6 across 6 ecosystems)
Debian:10(1)
PackageVulnerable rangeFixed inDependents
htmldoc1.9.3-1, 1.9.3-1+deb10u11.9.3-1+deb10u2—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
htmldoc—1.9.11-4—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
htmldoc—1.9.11-4—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
htmldoc—1.9.11-4—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
htmldoc—1.9.11-4—
Debian:9(1)
PackageVulnerable rangeFixed inDependents
htmldoc1.8.27-81.8.27-8+deb9u1—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(2)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 8× in last 7d / 29× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 148 total refreshes for this CVE.

  1. 2026-09-07 15:58 UTCEPSS rescore
  2. 2026-09-06 13:44 UTCEPSS rescore
  3. 2026-09-06 13:44 UTCEPSS rescore
  4. 2026-09-05 18:55 UTCOSV refresh
  5. 2026-09-05 15:25 UTCEPSS rescore
  6. 2026-09-04 13:57 UTCEPSS rescore
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  20. 2026-08-19 17:01 UTCEPSS rescore
  21. 2026-08-19 05:59 UTCOSV refresh
  22. 2026-08-18 13:45 UTCEPSS rescore
  23. 2026-08-17 13:43 UTCEPSS rescore
  24. 2026-08-16 14:52 UTCEPSS rescore
  25. 2026-08-16 02:11 UTCEPSS rescore
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  1. 2026-08-15 01:27 UTCEPSS rescore
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  3. 2026-08-12 13:47 UTCEPSS rescore
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  5. 2026-08-09 13:43 UTCEPSS rescore
  6. 2026-08-08 16:33 UTCEPSS rescore
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  8. 2026-08-06 13:43 UTCEPSS rescore
  9. 2026-08-05 19:14 UTCEPSS rescore
  10. 2026-08-04 15:06 UTCEPSS rescore
  11. 2026-08-04 10:34 UTCEPSS rescore
  12. 2026-08-04 01:27 UTCOSV refresh
  13. 2026-08-03 10:32 UTCEPSS rescore
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  19. 2026-07-26 14:52 UTCEPSS rescore
  20. 2026-07-25 14:15 UTCEPSS rescore
  21. 2026-07-24 14:15 UTCEPSS rescore
  22. 2026-07-23 14:15 UTCEPSS rescore
  23. 2026-07-23 01:57 UTCEG score recompute
  24. 2026-07-22 22:44 UTCEG score recompute
  25. 2026-07-22 14:05 UTCEPSS rescore
  26. 2026-07-21 15:22 UTCEPSS rescore
  27. 2026-07-21 15:22 UTCEPSS rescore
  28. 2026-07-20 17:04 UTCEPSS rescore
  29. 2026-07-19 14:28 UTCEPSS rescore
  30. 2026-07-19 02:26 UTCEPSS rescore
  31. 2026-07-18 10:02 UTCEPSS rescore
  32. 2026-07-17 20:29 UTCOSV refresh
  33. 2026-07-16 17:00 UTCEPSS rescore
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  41. 2026-07-11 08:25 UTCEPSS rescore
  42. 2026-07-09 19:07 UTCEPSS rescore
  43. 2026-07-08 15:12 UTCEPSS rescore
  44. 2026-07-07 13:43 UTCEPSS rescore
  45. 2026-07-06 16:25 UTCEPSS rescore
  46. 2026-07-06 02:21 UTCEPSS rescore
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  48. 2026-07-05 02:28 UTCEPSS rescore
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  50. 2026-07-04 06:29 UTCEPSS rescore
  51. 2026-07-04 06:29 UTCEPSS rescore
  52. 2026-07-02 16:57 UTCEPSS rescore
  53. 2026-07-01 15:03 UTCEPSS rescore
  54. 2026-06-30 23:20 UTCEPSS rescore
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  56. 2026-06-29 18:23 UTCOSV refresh
  57. 2026-06-29 14:04 UTCEPSS rescore
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  75. 2026-06-19 19:24 UTCEPSS rescore

Frequently asked(5)

What is CVE-2021-23165?
CVE-2021-23165 is a critical vulnerability published on March 16, 2022. A flaw was found in htmldoc before v1.9.12. Heap buffer overflow in pspdfprepareoutpages(), in ps-pdf.cxx may lead to execute arbitrary code and denial of service.
When was CVE-2021-23165 disclosed?
CVE-2021-23165 was first published in the National Vulnerability Database on March 16, 2022, with the most recent update on February 5, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-23165 actively exploited?
CVE-2021-23165 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 4% probability of exploitation in the next 30 days, which ranks it in the top 11.6% of all scored CVEs.
What is the CVSS score of CVE-2021-23165?
CVE-2021-23165 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2021-23165?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-23165, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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