PatchTheCVECVE-2026-40521: FrontAccounting before 2.4.20 contains a path traversal vulnerability in the attachment upload handler that al
CVE-2026-40521 is a high-severity flaw (CVSS 8.8) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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 remo
Why this priority
- High severity
- CISA SSVC: public proof of concept
A fixed release or distro patch exists.
Risk facts
| CVSS score | 8.8 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | Low |
| User interaction | None |
| EPSS exploit chance | 1.0% (top 38%) |
| CISA exploited list | No |
| Weakness | CWE-22 |
| Published | 2026-06-29 |
| Last modified | 2026-10-23 |
Last updated 2026-10-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Timeline
- Published CVE record published
- Updated Record last modified
Exact fixes by distribution
Public exploits and detection
Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-40521?
No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.
Is CVE-2026-40521 being exploited?
CVE-2026-40521 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-40521 affect?
CVE-2026-40521 affects affected software. Severity is high (CVSS 8.8). 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. A
How urgent is CVE-2026-40521?
Priority 49/100. High severity; CISA SSVC: public proof of concept