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Fencer Vulns
medium 5.5

CVE-2021-40985 json

A stack-based buffer under-read in htmldoc before 1.9.12, allows attackers to cause a denial of service via a crafted BMP image to image_lo…

published 2021-11-03 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-28138

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 61%
public exploits
0
none known

Summary

A stack-based buffer under-read in htmldoc before 1.9.12, allows attackers to cause a denial of service via a crafted BMP image to image_load_bmp.

Patch / fix

  • htmldoc_project htmldoc 1.9.12
  • htmldoc Debian 14, Debian 13, Debian 12 1.9.13-1

debian advisories DEBIAN-CVE-2021-40985

  • htmldoc Ubuntu Pro 14.04 LTS 1.8.27-8ubuntu1+esm3
  • htmldoc Ubuntu Pro 16.04 LTS 1.8.27-8ubuntu1.1+esm2
  • htmldoc Ubuntu Pro 18.04 LTS 1.9.2-1ubuntu0.2+esm1
  • htmldoc Ubuntu Pro 20.04 LTS 1.9.7-1ubuntu0.3+esm1

ubuntu advisories UBUNTU-CVE-2021-40985

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • htmldoc Subscription Management Tool 11 SP3 1.8.27-170.4.3.1

suse advisories SUSE-SU-2021:14869-1

  • htmldoc openSUSE Tumbleweed 1.9.12-2.1

opensuse advisories openSUSE-SU-2024:11611-1

  • htmldoc Arch Linux 1.9.13-1

arch linux advisories AVG-2521

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-40985 updated cvss 6.5

htmldoc: buffer overflow may lead to DoS via a crafted BMP image

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.94% chance of exploitation in the next 30 days, higher than 61% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/michaelrsweet/htmldoc/issues/444 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:N/A:P

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.