Auth bypass in Audiocodes Fax Server
CVE-2025-34331
AudioCodes Fax Server and Auto-Attendant IVR appliances versions up to and including 2.6.23 contain an unauthenticated file read vulnerability via the download.php script. The endpoint exposes a file download mechanism that lacks access control, allowing remote, unauthenticated users to request files stored on the appliance based solely on attacker-supplied path and filename parameters. While limited to specific file extensions permitted by the application logic, sensitive backup archives can be retrieved, exposing internal databases and credential hashes. Successful exploitation may lead to disclosure of administrative password hashes and other sensitive configuration data.
Vulnerability class: Broken Authentication
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.005 (42.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 42nd percentile — 42.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · 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-unauthenticated-file-… (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2025-34331?
- CVE-2025-34331 is a high-severity vulnerability in Audiocodes Fax Server, classified under Missing Authentication for Critical Function. CVSS score: 7.5/10. Published 2025-11-19.
- How severe is CVE-2025-34331?
- High severity. CVSS v3 base score is 7.5 out of 10.