Cisco Unity Connection up to 15SU3 API path traversal

Summaryinfo

A vulnerability labeled as critical has been found in Cisco Unity Connection. Affected by this issue is some unknown functionality of the component API Handler. The manipulation results in path traversal. This vulnerability is known as CVE-2026-20034. It is possible to launch the attack remotely. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as critical, was found in Cisco Unity Connection. Affected is an unknown part of the component API Handler. The manipulation with an unknown input leads to a path traversal vulnerability. CWE is classifying the issue as CWE-35. The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize '.../...//' (doubled triple dot slash) sequences that can resolve to a location that is outside of that directory. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

A vulnerability in the web-based management interface of Cisco Unity Connection could allow an authenticated, remote attacker to execute arbitrary code on an affected device. This vulnerability is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by submitting a crafted API request. A successful exploit could allow the attacker to execute arbitrary code as root, possibly resulting in the complete compromise of a targeted device. To exploit this vulnerability, the attacker must have valid user credentials on the affected device.

The advisory is shared for download at sec.cloudapps.cisco.com. This vulnerability is traded as CVE-2026-20034 since 10/08/2025. The exploitability is told to be easy. It is possible to launch the attack remotely. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 07/02/2026). The MITRE ATT&CK project declares the attack technique as T1006.

Upgrading eliminates this vulnerability.

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Productinfo

Type

• Unified Communication Software

Vendor

• Cisco

Name

• Unity Connection

Version

• 12.5(1)
• 12.5(1)SU1
• 12.5(1)SU2
• 12.5(1)SU3
• 12.5(1)SU4
• 12.5(1)SU5
• 12.5(1)SU6
• 12.5(1)SU7
• 12.5(1)SU8
• 12.5(1)SU8a
• 12.5(1)SU9
• 14
• 14SU1
• 14SU2
• 14SU3
• 14SU3a
• 14SU4
• 15
• 15SU1
• 15SU2
• 15SU3

License

• commercial

Website

• Vendor: https://www.cisco.com/

CPE 2.3info

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CPE 2.2info

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