CVE-2025-34329: Audiocodes Fax Server unrestricted file upload (CVSS 9.8)

Description

AudioCodes Fax Server and Auto-Attendant IVR appliances versions up to and including 2.6.23 expose an unauthenticated backup upload endpoint at AudioCodes_files/ajaxBackupUploadFile.php in the F2MAdmin web interface. The script derives a backup folder path from application configuration, creates the directory if it does not exist, and then moves an uploaded file to that location using the attacker-controlled filename, without any authentication, authorization, or file-type validation. On default Windows deployments where the backup directory resolves to the system drive, a remote attacker can upload web server or interpreter configuration files that cause a log file or other server-controlled resource to be treated as executable code. This allows subsequent HTTP requests to trigger arbitrary command execution under the web server account, which runs as NT AUTHORITY\\SYSTEM.

CVSS 3.1 breakdown

Attack vectorNetwork

Attack complexityLow

Privileges requiredNone

User interactionNone

ScopeUnchanged

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Affected products

Audiocodes Fax Server≤ 2.6.23

Audiocodes Interactive Voice Response≤ 2.6.23

Remediation

No fixed version is recorded in the NVD data. Check the vendor advisory for the latest guidance.

References

https://pierrekim.github.io/advisories/2025-audiocodes-fax-ivr.txtExploitThird Party Advisory
https://pierrekim.github.io/blog/2025-11-20-audiocodes-fax-ivr-8-vulnerabilities.htmlExploitThird Party Advisory
https://www.audiocodes.com/media/g1in2u2o/0548-product-notice-end-of-service-for-audiocodes-auto-attendant-ivr-solution.pdfProduct
https://www.vulncheck.com/advisories/audiocodes-fax-ivr-appliance-unauthenticated-backup-upload-rce-via-ajaxbackupuploadfileThird Party Advisory

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

Frequently asked

Is CVE-2025-34329 being actively exploited?

CVE-2025-34329 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 1.12%.

How severe is CVE-2025-34329?

CVE-2025-34329 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 1.12% probability of exploitation.

Which products are affected by CVE-2025-34329?

Affected products include Audiocodes Fax Server, Audiocodes Interactive Voice Response.

How do I fix CVE-2025-34329?

Apply the vendor's patch or advisory guidance, then verify no affected versions remain across your devices.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2025-34329 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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