Paper/Archive/CVE-2026-25923

CVE-2026-25923

My-Little-Forum mylittleforum — Phar Deserialization leading to Arbitrary File Deletion in my little forum

CVSS 9.1 (NVD)9.1 / 10 × 3027.3 Not in CISA KEV+300.0 EPSS percentile 42.9.429 × 208.6 Exploit: SSVC poc+1010.0 SSVC exploitation: poc+100.0

Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource

mylittleforum< 20260208.1–CNA

Scores by source

NVD9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

GitHub_M (CNA)8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CISA ADPSSVCExploitation: poc · Automatable: yes · Technical impact: partial

References

refgithub.com/My-Little-Forum/mylittleforum/security/advisories/GHSA-wr9p-3c3g-78fw refgithub.com/My-Little-Forum/mylittleforum/releases/tag/20260208.1