CVE-2021-23180

Exp

A flaw was found in htmldoc in v1.9.12 and before. Null pointer dereference in file_extension(),in file.c may lead to execute arbitrary code and denial of service.

Published: 2022-03-02 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-23180 is rated High Exploit Risk (70.2/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.27%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2021-23180

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-23180

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.28% 1.27% +0.99%
2 2025-11-21 0.45% 0.28% -0.17%
3 2025-11-18 — 0.45% —

Full EPSS history (13 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-23180

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 [email protected]
6.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 6.4 [email protected]

Weakness enumeration for CVE-2021-23180

OS Trackers for CVE-2021-23180

vendor priority summary link
debian unimportant CVE-2021-23180 unimportant priority: Debian including 1 source packages (htmldoc), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-23180
gentoo normal CVE-2021-23180: 1 GLSA(s) (202405-07), 1 atom(s) (app-text/htmldoc); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-23180
suse critical — https://www.suse.com/security/cve/CVE-2021-23180/
ubuntu medium CVE-2021-23180 medium priority: Ubuntu including 1 source packages (htmldoc), 16 status rows across 16 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 10, released 3, needed 2, ignored 1. https://ubuntu.com/security/CVE-2021-23180

Affected software / configurations for CVE-2021-23180

Vendor Product Version Raw CPE
htmldoc_project htmldoc <= 1.9.12 cpe:2.3:a:htmldoc_project:htmldoc:*:*:*:*:*:*:*:*

References for CVE-2021-23180

cvelogic Threat Intelligence