VulnerabilityPublished 5 Nov 2025Updated 4 Dec 2025

CVE-2025-20303: Cisco Identity Services Engine Software · Cross-site Scripting

Affects Cisco Identity Services Engine SoftwareSource CVE Database V5

Not known to be exploited · CVSS 5.4 Medium.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

5.4Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 3.8% chance of exploitation in 30 days – higher than 90% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: Required
Scope: Changed
Confidentiality: Low
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 5 Nov 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Cisco Cisco Identity Services Engine Software	Affected 3.1.0 – 3.4.0 4 affected builds	Fixed in–

AI-suggested

Apply Cisco's security patches and updates for Cisco ISE versions affected by CVE-2025-20303 as soon as they become available to remediate the vulnerability.
Restrict access to the Cisco ISE management interface to trusted administrative networks and enforce strong multi-factor authentication (MFA) to reduce the risk of low-privileged account compromise.
Implement strict input validation and output encoding on all user-supplied data within the management interface to prevent injection of malicious scripts.
Monitor and audit user activities on the Cisco ISE interface for unusual or unauthorized actions that may indicate exploitation attempts.
Educate administrators and users about phishing and social engineering risks to minimize the likelihood of user interaction triggering reflected XSS attacks.
Employ web application firewalls (WAFs) with rules tuned to detect and block reflected XSS payloads targeting the Cisco ISE interface.
Regularly review and minimize the number of users with access to the management interface, enforcing the principle of least privilege.
Conduct periodic security assessments and penetration testing focused on the management interface to identify and remediate similar injection vulnerabilities proactively.

Description

CVE-2025-20303 is a medium-severity reflected Cross-site Scripting (XSS) vulnerability in Cisco Identity Services Engine (ISE) web management interface. It allows an authenticated attacker with low privileges to inject malicious scripts that execute in the context of the interface, potentially exposing sensitive browser-based information. Exploitation requires user interaction and low-privileged authentication. The vulnerability affects multiple versions of Cisco ISE from 3.1.0 through 3.4 Patch 3. While no known exploits are reported in the wild, successful attacks could compromise confidentiality and integrity of session data. European organizations using Cisco ISE for network access control and policy enforcement should prioritize patching and implement strict input validation and access controls to mitigate risk. Countries with high Cisco ISE adoption and critical infrastructure reliance on network access control are most at risk.

Impact

For European organizations, the impact of CVE-2025-20303 can be substantial due to the widespread use of Cisco ISE in securing network access and enforcing policy compliance. Successful exploitation could lead to unauthorized disclosure of sensitive session information, enabling attackers to hijack administrative sessions or escalate privileges within the management interface. This compromises the confidentiality and integrity of network access controls, potentially allowing attackers to manipulate authentication and authorization policies. While availability is not directly impacted, the indirect effects of compromised management interfaces could disrupt network security operations. Organizations in sectors such as finance, telecommunications, government, and critical infrastructure are particularly at risk, as they rely heavily on Cisco ISE for secure network segmentation and access control. The requirement for low-privileged authentication reduces the attack surface but does not eliminate risk, especially in environments with many users or weak credential management. The need for user interaction limits automated exploitation but targeted phishing or social engineering attacks could facilitate triggering the vulnerability. Overall, the vulnerability poses a moderate risk to European entities, warranting prompt remediation to prevent lateral movement and data breaches.

References

sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ise-multiple-vulns-O9BESWJH (opens in a new tab)

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What to do

Affected software

Description

AI analysisMachine-generated, updated 11 Dec 2025, 22:17 UTC

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