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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.

PUBLISHED Reserved 2026-04-13 | Published 2026-06-29 | Updated 2026-07-14 | Assigner VulnCheck




HIGH: 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

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

Problem types

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Product status

Default status
affected

Any version before 2.4.20
affected

701fea6848da4a02fb83d30f07a9c0473d6b7e33 (git)
unaffected

Credits

Jiva (JivaSecurity) finder

References

jivasecurity.com/...ing-rce-attachment-upload-cve-2026-40521 technical-description exploit

sourceforge.net/p/frontaccounting/news/2026/04/release-2420/ release-notes

github.com/...ommit/701fea6848da4a02fb83d30f07a9c0473d6b7e33 patch

www.vulncheck.com/...ath-traversal-rce-via-attachment-upload third-party-advisory

cve.org (CVE-2026-40521)

nvd.nist.gov (CVE-2026-40521)

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