Denial of service in Cisco Enterprise Chat and Email

1) Incorrect Regular Expression

EUVDB-ID: #VU106918

Risk: High

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2025-20139

CWE-ID: CWE-185 - Incorrect Regular Expression

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to insufficient input validation when processing regular expressions in chat messaging features. A remote attacker can pass specially crafted data to the application and perform regular expression denial of service (ReDos) attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Enterprise Chat and Email: 12.5 - 12.6

CPE2.3

• cpe:2.3:a:cisco_systems:enterprise_chat_and_email:*:*:*:*:*:*:*:*
• cpe:2.3:a:cisco_systems:enterprise_chat_and_email:12.5:*:*:*:*:*:*:*
• cpe:2.3:a:cisco_systems:enterprise_chat_and_email:12.6:*:*:*:*:*:*:*

External links

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ece-dos-tC6m9GZ8

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.