CVE-2026-40521

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.

CVSS 4.0

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

CVSS 3.1

8.8CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS

1.0% chance of exploitation in the next 30 days; higher than 61% of CVEs (scores of 2026-10-25)

CWE

CWE-22

Published

2026-06-29

Modified

2026-10-23

Record from

the NVD, synced 2026-10-24

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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