Vulnerability · Published Jun 29, 2026 · Assigned by VulnCheck
CVE-2026-40521FrontAccounting < 2.4.20 Path Traversal RCE via attachment upload
High 8.8
In plain English
A high-severity path traversal in FrontAccounting from FrontAccounting. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 1.0% (higher than 62% of all known vulnerabilities).
Official description
FrontAccounting before 2.4.20 contains a path traversal vulnerability in the attachment upload handler that allows authenticated attackers to execute arbitrary code by uploading files with traversal sequences in the unique_name parameter. Attackers can supply path traversal sequences ../../../shell.php to write files outside the intended attachments directory into the web root, and by uploading PHP files without extension validation, achieve remote code execution as the web server user.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| FrontAccounting | FrontAccounting | 0 – before 2.4.20 |
Weakness: CWE-22 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
References
- https://jivasecurity.com/writeups/frontaccounting-rce-attachment-upload-cve-2026-40521 technical-description, exploit
- https://sourceforge.net/p/frontaccounting/news/2026/04/release-2420/ release-notes
- https://github.com/FrontAccountingERP/FA/commit/701fea6848da4a02fb83d30f07a9c0473d6b7e33 patch
- https://www.vulncheck.com/advisories/frontaccounting-path-traversal-rce-via-attachment-upload third-party-advisory