Deserialization in Cisco Identity Services Engine Software

CVE-2025-20124

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.

Vulnerability class: Insecure Deserialization

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.9 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:H.

EPSS exploit prediction

EPSS: 0.185 (97.2th percentile), scored .

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 97th percentile — 97.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2025-20124: held from 0.185 to 0.185.

EPSS over last 30 days · oldest: 0.185 · newest: 0.185 · change: 0.000

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-20124?
CVE-2025-20124 is a critical-severity vulnerability in Cisco Identity Services Engine Software, classified under Deserialization of Untrusted Data. CVSS score: 9.9/10. Published 2025-02-05.
How severe is CVE-2025-20124?
Critical severity. CVSS v3 base score is 9.9 out of 10.
Is CVE-2025-20124 known to be exploited?
6 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.