Cisco Unified Contact Center Express: Deserialization of Untrusted Data
CVE-2025-20276 is a high-severity deserialization of untrusted data vulnerability in Cisco Unified Contact Center Express from Cisco, with a CVSS 3.1 base score of 7.2 out of 10. It can be exploited remotely over the network by an attacker with administrator privileges, without any action from a user. Affected Cisco Unified Contact Center Express versions: 10.6(1); 10.5(1)SU1; 10.6(1)SU3, 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 0.48% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Cisco Unified Contact Center Express you run against the affected versions below, and install the vendor's latest release.
- 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 Unified Contact Center Express | 10.6(1); 10.5(1)SU1; 10.6(1)SU3; 12.0(1); 10.0(1)SU1; 10.6(1)SU1; 11.0(1)SU1; 11.5(1)SU1; and 32 more ranges | Not stated |
| Cisco | Unified Contact Center Express | 8.5\(1\); 9.0\(2\)su3es04; 10.0\(1\)su1; 10.0\(1\)su1es04; 10.5\(1\); 10.5\(1\)su1; 10.5\(1\)su1es10; 10.6\(1\); and 32 more ranges | Not stated |
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
- HighAdministrator-level access is required first.
- 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:H/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 3.8 | Low | CNA (cisco.com) |
| CVSS 3.1 | 7.2 | High | NVD |
Official description
A vulnerability in the web-based management interface of Cisco Unified CCX could allow an authenticated, remote attacker to execute arbitrary code on an affected device. To exploit this vulnerability, the attacker must have valid administrative credentials. This vulnerability is due to insecure deserialization of Java objects by the affected software. An attacker could exploit this vulnerability by sending a crafted Java object to an affected device. A successful exploit could allow the attacker to execute arbitrary code on the underlying operating system of an affected device as a low-privilege user. A successful exploit could also allow the attacker to undertake further actions to elevate their privileges to root.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Deserialization of Untrusted Data
The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.
How developers prevent this class of flaw
- If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
- When deserializing data, populate a new object rather than just deserializing. The result is that the data flows through safe input validation and that the functions are safe.
- Explicitly define a final object() to prevent deserialization.
More Deserialization of Untrusted Data vulnerabilities (CWE-502)
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
Advisories
Other vulnerabilities in Cisco Unified Contact Center Express
- 7.2 High severity
- 7.2 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 8.8 High severity
- 7.8 High severity
Recent Deserialization of Untrusted Data vulnerabilities
- 9.3 Critical severity
- 9.8 Critical severity
- 7.2 High severity
- 9.8 Critical severity
- 9.0 Critical severity
- 8.8 High severity
Spotted an error? Tell us.