CVE-2026-20211

CVE CVE-2026-20211EUVD EUVD-2026-81099Published 2026-09-16T20:04:10.000ZLast changed 2026-09-17T11:39:23.000ZCVSS 9.1

What the advisory describes

A vulnerability in Cisco ISE could allow an authenticated, remote attacker to execute arbitrary commands on the underlying operating system of an affected device. To exploit this vulnerability, the attacker must have valid high-privileged 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 serialized Java object to an affected device. A successful exploit could allow the attacker to obtain user-level access to the underlying operating system and then elevate privileges to root. In single-node deployments, successful exploitation of this vulnerability could cause the affected ISE node to become unavailable, resulting in a DoS condition. In that condition, endpoints that have not already authenticated would be unable to access the network until the node is restored.

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

• Cisco — Cisco Identity Services Engine Software 3.1.0 p11; 3.3 Patch 10; 3.4 Patch 6; 3.4 Patch 4; 3.5 Patch 3; 3.4 Patch 2; 3.4 Patch 1; 3.1.0; 3.1.0 p7; 3.3 Patch 5; 3.2.0 p4; 3.3 Patch 3; 3.1.0 p4; 3.3 Patch 6; 3.2.0 p6; 3.1.0 p3; 3.2.0 p5; 3.3 Patch 2; 3.1.0 p9; 3.2.0 p3; 3.1.0 p2; 3.1.0 p6; 3.3 Patch 1; 3.1.0 p8; 3.5 Patch 1; 3.5 Patch 2; 3.4 Patch 3; 3.1.0 p1; 3.2 Patch 9; 3.1.0 p72; 3.3 Patch 11; 3.3 Patch 4; 3.3 Patch 9; 3.2 Patch 10; 3.4 Patch 5; 3.2.0 p1; 3.3 Patch 8; 3.1.0 p10; 3.2.0 p7; 3.4.0; 3.2.0 p2; 3.3.0; 3.3 Patch 7; 3.2 Patch 8; 3.2.0; 3.5.0; 3.1.0 p5

The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.

Carried in the product catalogue

An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.

• Cisco — Identity Services Engine Software

Patchlage reports hits and suspected hits. About everything else this system says nothing — neither this page nor the situation report ever claims that an estate is safe.