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Stored cross-site scripting in phpMyFAQ via SVG DTD entities

Priority MEDIUM 56CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Passive
Attack complexity
Low
Attack requirements
None
Impact type
Cross-site scripting
Confidentiality · integrity · availability
Low · Low · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-79.

Summary

phpMyFAQ from 4.2.0-alpha before 4.2.0-beta is affected. Its SvgSanitizer fails to neutralize script in uploaded SVG files, allowing stored cross-site scripting (CWE-79) through XML DTD custom entities. A user with FAQ_EDIT permission can upload a crafted SVG, and the script runs when a viewer clicks the link, which can hijack admin sessions.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Description from the CNA

phpMyFAQ 4.2.0-alpha before 4.2.0-beta contains a stored cross-site scripting vulnerability in SvgSanitizer that allows users with FAQ_EDIT permission to bypass sanitization using XML DTD custom entities. Attackers can upload an SVG defining an entity that expands to javascript in an anchor href, executing script when viewers click it to hijack admin sessions.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00223 12th percentileScored 2026-11-07
Fix Fixed phpMyFAQ (thorsten): 4.2.0-beta

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

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

Affected products

VendorProductAffected versionsFixed inStatusSource
thorstenphpMyFAQ4.2.0-alpha to before 4.2.0-beta4.2.0-betaPatch availableCNA
  • phpMyFAQ Vendorthorsten Affected 4.2.0-alpha to before 4.2.0-beta Fixed in 4.2.0-beta Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:phpmyfaq:phpmyfaq:*:*:*:*:*:*:*:*——thorsten
  • cpe:2.3:a:phpmyfaq:phpmyfaq:*:*:*:*:*:*:*:* Versions — — ·thorsten

Remediation

Upgrade phpMyFAQ to 4.2.0-beta, the fixed version.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

  • Fix · CNA phpMyFAQ (thorsten) Fixed in 4.2.0-beta

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    thorsten phpMyFAQ 4.2.0-beta

    24 records Highest priority Priority HIGH 10 HIGH, 10 MEDIUM, 4 LOW

    Other records, highest priority first

    • TI-2026-76108 Unauthenticated denial of service in phpMyFAQ API paginationPriority HIGH 77
    • TI-2026-76115 Authorization bypass in phpMyFAQ REST API edits restricted FAQsPriority HIGH 73
    • TI-2026-76092 phpMyFAQ e-mail change lacks password check, enabling takeoverPriority HIGH 73

Timeline

  1. 2026-10-18 Threatist record created from CVE-2026-111903
  2. 2026-10-18 Alias added: GHSA-4fcw-x9vq-q4pp
  3. 2026-10-20 CISA SSVC decision points changed
  4. 2026-10-20 Priority changed: LOW → MEDIUM

References

  • TI-2023-00296 Improper Authentication in thorsten/phpmyfaq CVSS 3.1CRITICAL 9.8
  • TI-2026-76118 Authentication bypass in phpMyFAQ via WebAuthn credential injection CVSS 4.0CRITICAL 9.3
  • TI-2026-32868 phpMyFAQ - Unauthenticated Two-Factor Authentication Brute-Force via /admin/check Endpoint CVSS 4.0CRITICAL 9.3
  • TI-2026-76108 Unauthenticated denial of service in phpMyFAQ API pagination CVSS 4.0HIGH 8.7
  • TI-2026-53313 phpMyFAQ 3.1.0 through 4.1.6 Authentication Bypass via LDAP CVSS 4.0HIGH 8.8
  • TI-2026-34083 phpMyFAQ - Unauthenticated Information Disclosure via getIdFromSolutionId Permission Bypass CVSS 4.0HIGH 8.7
See all 224 →

Sources