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TI-2021-12836 Aliases CVE-2021-33391GHSA-wfrp-xv2m-8j85

An issue in HTACG HTML Tidy v5.7.28 allows attacker to execute arbitrary code via the -g…

Priority HIGH 82CWE-416Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
No fix listed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-416 and the CVSS impact.

Summary

An issue in HTACG HTML Tidy v5.7.28 allows attacker to execute arbitrary code via the -g option of the CleanNode() function in gdoc.c.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.01128 66th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
——all versions—No fix listedCNA
  • — Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 2

CPEVersionsRoleVendor
cpe:2.3:a:htacg:tidy:5.7.28:*:*:*:*:*:*:*5.7.28VulnerableHTACG
cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*not specified by NVDRunning onLinux
  • cpe:2.3:a:htacg:tidy:5.7.28:*:*:*:*:*:*:* Versions 5.7.28 Vulnerable ·HTACG
  • cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Linux

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-33391
  2. 2026-10-03 Alias added: GHSA-wfrp-xv2m-8j85

References

Exploit 1

  • TI-2025-05899 HTACG tidy-html5 alloc.c defaultAlloc memory leak CVSS 4.0MEDIUM 4.8
  • TI-2015-04650 Heap-based buffer overflow in the ParseValue function in lexer.c in tidy before 4.9.31… CVSS 2.0MEDIUM 6.8
  • TI-2017-12775 In Tidy 5.7.0, the prvTidyTidyMetaCharset function in clean.c allows attackers to cause a… CVSS 3.1HIGH 7.5
  • TI-2017-09969 In Tidy 5.5.31, the IsURLCodePoint function in attrs.c allows attackers to cause a denial… CVSS 3.0HIGH 7.5
  • TI-2015-04651 The ParseValue function in lexer.c in tidy before 4.9.31 allows remote attackers to cause… CVSS 2.0MEDIUM 4.3

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences