RCE in Audiocodes Fax Server
CVE-2025-34334
AudioCodes Fax Server and Auto-Attendant IVR appliances versions up to and including 2.6.23 are vulnerable to an authenticated command injection in the fax test functionality implemented by AudioCodes_files/TestFax.php. When a fax "send" test is requested, the application builds a faxsender command line using attacker-supplied parameters and passes it to GlobalUtils::RunBatchFile without proper validation or shell-argument sanitization. The resulting batch file is written into a temporary run directory and then executed via a backend service that runs as NT AUTHORITY\\SYSTEM. An authenticated attacker with access to the fax test interface can craft parameter values that inject additional shell commands into the generated batch file, leading to arbitrary command execution with SYSTEM privileges. In addition, because the generated batch files reside in a location with overly permissive file system permissions, a local low-privilege user on the server can modify pending batch files to achieve the same elevation.
Vulnerability class: Command Injection (OS Command Injection)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.034 (88.5th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 89th percentile — 88.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.034 · newest: 0.034 · change: 0.000
Affected products
Weakness classification (CWE)
References
- www.audiocodes.com/media/g1in2u2o/0548-product-notice-end-of-service-for-audioc… (Product, vendor-advisory, patch, mitigation)
- pierrekim.github.io/blog/2025-11-20-audiocodes-fax-ivr-8-vulnerabilities.html (Exploit, technical-description, Third Party Advisory, exploit)
- pierrekim.github.io/advisories/2025-audiocodes-fax-ivr.txt (Exploit, technical-description, Third Party Advisory, exploit)
- www.vulncheck.com/advisories/audiocodes-fax-ivr-appliance-authenticated-command… (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2025-34334?
- CVE-2025-34334 is a high-severity vulnerability in Audiocodes Fax Server, classified under OS Command Injection. CVSS score: 8.8/10. Published 2025-11-19.
- How severe is CVE-2025-34334?
- High severity. CVSS v3 base score is 8.8 out of 10.