Path Traversal Vulnerability in FrontAccounting by FrontAccounting
CVE-2026-40521

8.7HIGH

Key Information:

Vendor

Frontaccounting

Status
Frontaccounting
Vendor
CVE Published:
29 June 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-40521?

FrontAccounting versions before 2.4.20 are susceptible to a path traversal vulnerability present in the attachment upload handler. This vulnerability enables authenticated attackers to manipulate the unique_name parameter, allowing the inclusion of malicious path traversal sequences like '../../../shell.php'. By exploiting this flaw, attackers can upload files outside the designated attachments directory, impacting the web root area. This capability facilitates the execution of arbitrary PHP scripts without proper file extension validation, ultimately leading to remote code execution on the server.

Affected Version(s)

FrontAccounting 0

FrontAccounting 0 < 2.4.20

FrontAccounting 701fea6848da4a02fb83d30f07a9c0473d6b7e33

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-40521 - Proof of Concept

References

https://jivasecurity.com/writeups/frontaccounting-rce-att...
technical-descriptionexploit
https://sourceforge.net/p/frontaccounting/news/2026/04/re...
release-notes
https://github.com/FrontAccountingERP/FA/commit/701fea684...
patch

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Jiva (JivaSecurity)
.