CVE-2026-40521

HIGH
MEDIUM Priority: 0.09 BB Relevance: 68/100
Published: 2026-06-29 Modified: 2026-10-23 First seen: 2026-10-29 Status: active

Attack Surface

Network Low Complexity No Interaction Conf. Impact Integ. Impact

CVSS Vector Breakdown

AV: Network
AC: Low
PR: Low
UI: None
S: X
AT: None
VC: High
VI: High
VA: High

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.

Weakness Classification (1)

Bug Bounty Relevance

68 / 100
✓ Network accessible
✓ Low complexity
✓ No user interaction

CVSS Score

8.7 / 10.0 v4.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS — Exploitation Probability

0.98%
Raw Score 0.009770
Percentile 62.1%
Date 2026-10-29

EPSS Trend

2026-10-29
0.00977
2026-10-28
0.00977

Intelligence Sources

nvd ref →