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PatchSiren cyber security CVE debrief

CVE-2026-20147 Cisco CVE debrief

CVE-2026-20147 is a critical vulnerability in Cisco ISE and Cisco ISE-PIC that allows authenticated remote attackers to execute arbitrary commands on the underlying operating system of an affected device. To exploit this vulnerability, the attacker must have valid administrative credentials. This vulnerability is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by sending a crafted HTTP request 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 ISE deployments, successful exploitation of this vulnerability could cause the affected ISE node to become unavailable, resulting in a denial of service (DoS) condition. In that condition, endpoints that have not already authenticated would be unable to access the network until the node is restored.

Vendor
Cisco
Product
Cisco Identity Services Engine (ISE) and ISE-PIC
CVSS
CRITICAL 9.9
CISA KEV
Not listed in stored evidence
Original CVE published
2026-04-15
Original CVE updated
2026-07-08
Advisory published
2026-04-15
Advisory updated
2026-07-08

Who should care

Administrators and security teams responsible for Cisco ISE and Cisco ISE-PIC devices should prioritize patching this vulnerability to prevent potential exploitation. This includes teams managing network access, security operations, and vulnerability management, as well as operators overseeing affected product deployments.

Technical summary

The vulnerability is caused by insufficient validation of user-supplied input in Cisco ISE and Cisco ISE-PIC. An authenticated remote attacker with administrative credentials can exploit this vulnerability by sending a crafted HTTP request to an affected device, potentially leading to arbitrary command execution on the underlying operating system. Successful exploitation could allow the attacker to obtain user-level access to the underlying operating system and then elevate privileges to root. In single-node ISE deployments, this could cause the affected ISE node to become unavailable, resulting in a denial of service (DoS) condition, preventing endpoints that have not already authenticated from accessing the network until the node is restored.

Defensive priority

High

Recommended defensive actions

  • Apply patches or updates provided by Cisco to affected devices.
  • Restrict access to administrative interfaces to only trusted users.
  • Monitor network traffic for suspicious activity.
  • Implement additional security measures such as network segmentation and access controls.
  • Review compensating controls for exposed systems while remediation is scheduled and verified.
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review.
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented.

Evidence notes

The CVE record was published on 2026-04-15T17:17:02.410Z and has not been modified since then. The NVD entry is currently Analyzed. Evidence is limited to CVE and NVD information; further verification is recommended to assess affected deployments and validate vendor guidance.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-04-15T17:17:02.410Z and has not been modified since then. The NVD entry is currently Analyzed.