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
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.007 (49.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 49th percentile — 49.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.007 · change: +0.002
Affected products
- My-Little-Forum Mylittleforum — versions < 20260208.1
- Mylittleforum My Little Forum
Weakness classification (CWE)
References
- github.com/My-Little-Forum/mylittleforum/security/advisories/GHSA-wr9p-3c3g-78fw (Exploit, Mitigation, Vendor Advisory)
- github.com/My-Little-Forum/mylittleforum/releases/tag/20260208.1 (Product, 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.