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Medium

Cisco ISE Observable Response Discrepancy User Enumeration Vulnerability

IdentifiersCVE-2026-20195CWE-204· Observable Response Discrepancy

CVE-2026-20195 is a user enumeration vulnerability in an identity management API endpoint of Cisco Identity Services Engine (ISE). The issue exists because the affected endpoint returns distinguishable error messages or otherwise differentiated responses when processing requests associated with valid versus invalid accounts. An unauthenticated remote attacker can send a series of crafted requests to the API endpoint and analyze the observable differences in responses to determine which usernames are valid on the target system.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows an unauthenticated remote attacker to enumerate valid user accounts on an affected Cisco ISE device. This can disclose identity information about local or integrated accounts and materially reduce the effort required for subsequent password spraying, credential stuffing, brute-force attacks, or targeted social engineering against known-valid usernames.

Mitigation

If you can’t patch tonight, do this now.

Restrict network access to the affected identity management API endpoint to only trusted administrative hosts or management networks where possible. Monitor for repeated crafted requests to the endpoint indicative of username enumeration activity, and enforce compensating controls such as rate limiting, WAF/API gateway filtering, and strong authentication protections on downstream services. Specific vendor-recommended mitigations are not provided in the available content.

Remediation

Patch, then assume compromise.

Apply the Cisco-provided software update or fixed release for Cisco ISE that addresses CVE-2026-20195, in accordance with the relevant Cisco security advisory and product guidance. If fixed software information is not yet available in the provided content, that information is currently not available.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
Cisco SystemsIdentity Services Engineapplication
Cisco SystemsIseapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

2 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.

No news coverage yet. Advisories and community discussion only.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.
Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity1

Community discussion across Reddit, Mastodon, and other social sources.