Cisco Unity Connection: Path Traversal: '.../...//'
CVE-2026-20034 is a high-severity path traversal: '.../...//' vulnerability in Cisco Unity Connection from Cisco, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected Cisco Unity Connection versions: 12.5(1); 12.5(1)SU1; 12.5(1)SU2, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.71% chance of exploitation within 30 days, higher than 54% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Unity Connection to 14.0 or a later version.
- Read the advisory on sec.cloudapps.cisco.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Cisco | Cisco Unity Connection | 12.5(1); 12.5(1)SU1; 12.5(1)SU2; 12.5(1)SU3; 12.5(1)SU4; 14; 12.5(1)SU5; 14SU1; and 13 more ranges | Not stated |
| Cisco | Unity Connection | before 14.0; 14.0; 14su1; 14su2; 14su3; 14su4; 15.0; 15su1; and 2 more ranges | 14.0 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (cisco.com).
Official description
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Path Traversal: '.../...//'
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.
How developers prevent this class of flaw
- Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in Cisco Unity Connection
- 7.5 High severity
- 7.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 9.3 Critical severity
Recent Path Traversal: '.../...//' vulnerabilities
- 9.8 Critical severity
- 7.5 High severity
- 9.9 Critical severity
- 8.8 High severity
- 7.2 High severity
- 8.1 High severity
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