CVE-2026-40521Public exploitNetwork attack vector

Authenticated code execution via traversable attachment filename

Published Jun 29, 2026 · Updated Jun 29, 2026

Path traversal in FrontAccounting before 2.4.20 allows remote authenticated users to execute arbitrary code through attachment uploads. The includes/ui/attachment.inc handler uses the unique_name POST value directly in a path passed to move_uploaded_file and accepts executable PHP content. An authenticated account with attachment access can place a PHP file in the web root, where the web server executes it with its own privileges.

CVSS severity8.8
High
EPSS probability0.98%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in FrontAccounting before 2.4.20 allows remote authenticated users to execute arbitrary code through attachment uploads. The includes/ui/attachment.inc handler uses the unique_name POST value directly in a path passed to move_uploaded_file and accepts executable PHP content. An authenticated account with attachment access can place a PHP file in the web root, where the web server executes it with its own privileges.

The record

CVE
CVE-2026-40521
Published
Jun 29, 2026
Updated
Jun 29, 2026
Vendor
FrontAccounting
Product
FrontAccounting
Classifications
CWE-22, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 29, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 29, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <2.4.20

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

FrontAccounting · FrontAccountingversion=0 <2.4.20

Published CVSS scores

8.8VulnCheckCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
8.7VulnCheckCVSS: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 describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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