CVE intelligence and bounded remediation

CVE-2025-20124 — Cisco Identity Services Engine security vulnerability

Critical CVSS 9.9

A vulnerability in an API of Cisco ISE could allow an authenticated, remote attacker to execute arbitrary commands as the root user on an affected device. This vulnerability is due to insecure deserialization of user-supplied Java byte streams by the affected software. An attacker could exploit this vulnerability by sending a crafted serialized Java object to an affected API. A successful exploit could allow the attacker to execute arbitrary commands on the device and elevate privileges. Note: To successfully exploit this vulnerability, the attacker must have valid read-only administrative credentials. In a single-node deployment, new devices will not be able to authenticate during the reload time.

Severity
Critical
CVSS
9.9 (3.1)
Published
2025-02-05
CISA KEV
Not currently listed
Ecosystem
java/maven
Weaknesses
CWE-502

Affected products

  • cisco / identity_services_engine
  • cisco / identity_services_engine / 3.1.0
  • cisco / identity_services_engine / 3.2.0

Showing 3 representative product identities from 22 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Unsafe deserialization and object reconstruction

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Check exposure

  • Inventory serialization formats accepted from requests, queues, caches, files, cookies, and cross-service messages.
  • Trace whether untrusted input can select classes, types, callbacks, constructors, or object hooks during decoding.
  • Identify signing, schema validation, trust-boundary, and compatibility settings for each decoder.

Remediate safely

  • Replace native object deserialization with a data-only format and explicit schema validation.
  • If replacement is not immediate, use a safe decoder with a minimal type allowlist and disable polymorphic or executable hooks.
  • Update the affected library and add inert tests for unknown types, extra fields, malformed nesting, and unsigned data.

Authoritative sources

Complete CVE record and remediation plan

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