Arbitrary file upload in My-Little-Forum Mylittleforum
CVE-2026-25923
my little forum is a PHP and MySQL based internet forum that displays the messages in classical threaded view. Prior to 20260208.1, the application fails to filter the phar:// protocol in URL validation, allowing attackers to upload a malicious Phar Polyglot file (disguised as JPEG) via the image upload feature, trigger Phar deserialization through BBCode [img] tag processing, and exploit Smarty 4.1.0 POP chain to achieve arbitrary file deletion. This vulnerability is fixed in 20260208.1.
Vulnerability class: Unrestricted File Upload
EPSS: 0.004 (35.6th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H.
Affected products
- My-little-forum Mylittleforum — versions < 20260208.1
- Mylittleforum My_little_forum
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Mitigation, Vendor Advisory)
- security-advisories@github.com (Product, x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-25923?
- CVE-2026-25923 is a critical-severity vulnerability in My-Little-Forum Mylittleforum, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 9.1/10. Published 2026-02-09.
- How severe is CVE-2026-25923?
- Critical severity. CVSS v3 base score is 9.1 out of 10.