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CVE-2021-23180

A flaw was found in htmldoc in v1.9.12 and before. Null pointer dereference in file_extension()...

7.8 HighFix available

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.

Attack profile

How easy it is to exploit

Attack vector
Local
Complexity
Low
Privileges needed
None
User interaction
Required

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
High

Exploit likelihood

1.35%Down 0.2 points since Mar 3, 2022
90%50%10%1%

What each source reports

NVD Score used 7.8

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.

Record
CVE-2021-23180
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS 2.0
6.8 MediumAV:N/AC:M/Au:N/C:P/I:P/A:P
Weakness
CWE-476
Updated
2026-11-02
CVE List No score

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.

Record
CVE-2021-23180
Weakness
CWE-476
Updated
2026-11-02
EUVDEUVD-2021-10290 No score

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.

Record
EUVD-2021-10290
Updated
2026-11-03
GitHub AdvisoriesGHSA-77xx-wx8p-7pfj 7.8

A flaw was found in htmldoc in v1.9.12 and before. Null pointer dereference in file_extension()...

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.

Record
GHSA-77xx-wx8p-7pfj
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness
CWE-476
Updated
2026-11-02
OSV 7.8

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.

Record
CVE-2021-23180
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVDEBIAN-CVE-2021-23180 7.8

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.

Record
DEBIAN-CVE-2021-23180
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVUBUNTU-CVE-2021-23180 7.8

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.

Record
UBUNTU-CVE-2021-23180
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVMGASA-2021-0332 No score

Updated htmldoc packages fix security vulnerabilities

Updated htmldoc packages fix security vulnerabilities:

Integer overflow in the htmldoc 1.9.11 and before may allow attackers to execute arbitrary code and cause a denial of service that is similar to CVE-2017-9181 (CVE-2021-20308).

AddressSanitizer: double-free in function pspdf_export ps-pdf.cxx (CVE-2021-23158).

AddressSanitizer: heap-buffer-overflow in pspdf_prepare_outpages() in ps-pdf.cxx (CVE-2021-23165).

AddressSanitizer: SEGV in file_extension file.c (CVE-2021-23180).

AddressSanitizer: SEGV on unknown address 0x000000000014 (CVE-2021-23191).

AddressSanitizer: stack-buffer-overflow in parse_table ps-pdf.cxx (CVE-2021-23206).

AddressSanitizer: heap-buffer-overflow in pspdf_prepare_page(int) ps-pdf.cxx (CVE-2021-26252).

AddressSanitizer: heap-buffer-overflow on render_table_row() ps-pdf.cxx (CVE-2021-26259).

SEGV on unknown address 0x000000000000 (CVE-2021-26948).

Record
MGASA-2021-0332
Updated
2026-11-02
OSVUSN-5198-1 No score

htmldoc vulnerability

It was discovered that HTMLDOC improperly handled malformed URIs from an input html file. An attacker could use this to cause a denial of service.

Record
USN-5198-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
htmldoc
Debian:12
 before 1.9.11-4
1.9.11-4
htmldoc
Debian:13
 before 1.9.11-4
1.9.11-4
htmldoc
Debian:14
 before 1.9.11-4
1.9.11-4
htmldoc
Debian:9
From an advisory covering 10 CVEs
 before 1.8.27-8+deb9u1, plus listed versions
1.8.27-8
1.8.27-8+deb9u1
htmldoc
Debian:10
From an advisory covering 8 CVEs
 before 1.9.3-1+deb10u2, plus listed versions
1.9.3-11.9.3-1+deb10u1
1.9.3-1+deb10u2
htmldoc
Mageia:7
From an advisory covering 9 CVEs
 before 1.9.3-2.3.mga7
1.9.3-2.3.mga7
htmldoc
Mageia:8
From an advisory covering 9 CVEs
 before 1.9.8-1.2.mga8
1.9.8-1.2.mga8
htmldoc
Ubuntu:Pro:14.04:LTS
 All versions, plus listed versions
1.8.27-8ubuntu11.8.27-8ubuntu1+esm11.8.27-8ubuntu1+esm21.8.27-8ubuntu1+esm31.8.27-8ubuntu1+esm4
 None known
htmldoc
Ubuntu:Pro:16.04:LTS
 All versions, plus listed versions
1.8.27-8ubuntu11.8.27-8ubuntu1.11.8.27-8ubuntu1.1+esm11.8.27-8ubuntu1.1+esm21.8.27-8ubuntu1.1+esm3
 None known
htmldoc
Ubuntu:20.04:LTS
 before 1.9.7-1ubuntu0.2, plus listed versions
1.9.3-11.9.7-11.9.7-1build1
1.9.7-1ubuntu0.2

History

History
RecordedChangedSources
affected, facts
aliases, productsEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-23180 is a high vulnerability (CVSS 7.8) in Htmldoc Project Htmldoc, published June 3, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.35%, the 71st percentile. Fixed in htmldoc 1.9.11-4.

References

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