What’s Vulnerable › Vulnerabilities

CVE-2026-40521: FrontAccounting < 2.4.20 Path Traversal RCE via attachment upload

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.0% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-29 · updated 2026-10-23
• Weakness: CWE-22

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

• FrontAccounting: before 2.4.20 — fixed in 2.4.20

How to fix

Upgrade to a fixed version: FrontAccounting 2.4.20. Check the vendor advisory for mitigations.

References

• https://github.com/FrontAccountingERP/FA/commit/701fea6848da4a02fb83d30f07a9c0473d6b7e33
• https://jivasecurity.com/writeups/frontaccounting-rce-attachment-upload-cve-2026-40521
• https://sourceforge.net/p/frontaccounting/news/2026/04/release-2420/
• https://www.vulncheck.com/advisories/frontaccounting-path-traversal-rce-via-attachment-upload

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