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Fencer Vulns
medium 5.4

CVE-2026-34974 json

phpMyFAQ: SVG Sanitizer Bypass via HTML Entity Encoding leads to Stored XSS and Privilege Escalation

published 2026-04-01 7 mo ago modified 2026-07-24 3 mo ago also GHSA-5crx-pfhq-4hgg , EUVD-2026-18332

cvss
5.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 7%
public exploits
0
none known

Summary

phpMyFAQ is an open source FAQ web application. Prior to version 4.1.1, the regex-based SVG sanitizer in phpMyFAQ (SvgSanitizer.php) can be bypassed using HTML entity encoding in javascript: URLs within SVG <a href> attributes. Any user with edit_faq permission can upload a malicious SVG that executes arbitrary JavaScript when viewed, enabling privilege escalation from editor to full admin takeover. This issue has been patched in version 4.1.1.

Patch / fix

  • packagist thorsten/phpmyfaq 4.1.1
  • phpmyfaq phpmyfaq 4.1.1

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
7 mo ago

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/thorsten/phpMyFAQ/security/advisories/GHSA-5crx-pfhq-4hgg referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
GitHub 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
packagist thorsten/phpmyfaq
<4.1.1
4.1.1

Affected products

  • thorsten phpMyFAQ

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

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.