CVE-2026-24420

A logged‑in user without the dlattachment right can download FAQ attachments. This is due to a permissive permission check in attachment.php that treats the mere presence of a right key as authorization and a flawed group/user logic expression.

Details

In attachment.php, the access decision uses:
($groupPermission || ($groupPermission && $userPermission)) && isset($permission['dlattachment'])
isset() returns true even when the right value is false, and the logic simplifies to $groupPermission for some permission modes. As a result, a user without dlattachment can still access the attachment.

PoC

Precondition: A non‑admin user exists; an attachment is associated to a FAQ record; records.allowDownloadsForGuests = false.
Log in as a non‑admin user without dlattachment.
Request the attachment download endpoint.

curl -c /tmp/pmf_api_cookies.txt \
  -H 'Content-Type: application/json' \
  -d '{"username":"tester","password":"Test1234!"}' \
  http://192.168.40.16/phpmyfaq/api/v3.0/login

curl -i -b /tmp/pmf_api_cookies.txt \
  "http://192.168.40.16/phpmyfaq/index.php?action=attachment&id=1"

Impact

Unauthorized users can download attachments (confidentiality breach). Depending on content, this may expose sensitive documents.

CVE-2026-24420 has a CVSS score of 6.5 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (4.0.17); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-24420? CVE-2026-24420 is a medium-severity security vulnerability in phpmyfaq/phpmyfaq (composer), affecting versions <= 4.0.16. It is fixed in 4.0.17.
2. How severe is CVE-2026-24420? CVE-2026-24420 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which packages are affected by CVE-2026-24420?
   • phpmyfaq/phpmyfaq (composer) (versions <= 4.0.16)
   • thorsten/phpmyfaq (composer) (versions <= 4.0.16)
4. Is there a fix for CVE-2026-24420? Yes. CVE-2026-24420 is fixed in 4.0.17. Upgrade to this version or later.
5. Is CVE-2026-24420 exploitable, and should I be worried? Whether CVE-2026-24420 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-24420 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-24420?
   • Upgrade phpmyfaq/phpmyfaq to 4.0.17 or later
   • Upgrade thorsten/phpmyfaq to 4.0.17 or later