Evidence used
- No CISA KEV confirmation is currently recorded.
- The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
- EPSS is 0.58% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2026
CVE-2026-76423High confidence
Cisco ISE API Authentication Bypass Vulnerability
Cisco · Cisco Identity Services Engine Software
Official source article: Cisco CISCO-SA-ISE-MULTI-HRP9JQSQ ↗. Check the applicable product and release in the original source.
10.0CriticalCVSS 3.1
Within 72 hours
Patch availableCritical technical impact with a remotely reachable, unauthenticated path; no CISA KEV confirmation is currently recorded.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityCritical→Operational priority:Critical, unchanged from published severity.unchanged
Compensating controls
- Validate the affected product branch and deploy the verified fixed release.
- Restrict the affected network interface to trusted sources where business-safe.
- Monitor vendor guidance and exploitation sources for a material change.
Verification
- Confirm that the asset runs Cisco Cisco Identity Services Engine Software and falls inside the recorded affected range.
- Verify the installed build against the product-specific fixed version after deployment.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Critical technical impact with a remotely reachable, unauthenticated path; no CISA KEV confirmation is currently recorded.
Patch available01
What, why and how
A vulnerability in the REST API of Cisco ISE and Cisco ISE-PIC could allow an unauthenticated, remote attacker to gain administrative access to an affected device. This vulnerability is due to the REST API web service being exposed with insufficient authorization checks. An attacker could exploit this vulnerability by sending a crafted HTTP request to the exposed REST API port. A successful exploit could allow the attacker to read and modify ISE configuration and identity data with administrative privileges.
What
A vulnerability in the REST API of Cisco ISE and Cisco ISE-PIC could allow an unauthenticated, remote attacker to gain administrative access to an affected device. This vulnerability is due to the REST API web service being exposed with insufficient authorization checks. An attacker could exploit this vulnerability by sending a crafted HTTP request to the exposed REST API port. A successful exploit could allow the attacker to read and modify ISE configuration and identity data with administrative privileges.
Why
This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
What
A vulnerability in the REST API of Cisco ISE and Cisco ISE-PIC could allow an unauthenticated, remote attacker to gain administrative access to an affected device. This vulnerability is due to the REST API web service being exposed with insufficient authorization checks. An attacker could exploit this vulnerability by sending a crafted HTTP request to the exposed REST API port. A successful exploit could allow the attacker to read and modify ISE configuration and identity data with administrative privileges.
Why
This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material None recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.
- Likely attack path
- a network path → Authentication Bypass by Spoofing → cause the confidentiality, integrity or availability impact described by the vendor
- Attack surface
- Network
- Privileges required
- None: unauthenticated exploitation is possible
- User interaction
- None
- Attack complexity
- Low: no specialised conditions are recorded
- Security boundary
- Changed: exploitation can affect a different security authority
- Weakness
?
CWE means Common Weakness Enumeration: a standard category for the underlying weakness. - CWE-290 ↗
CWE-290: Authentication Bypass by Spoofing. This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:LCommon Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SChangedScope: The attack can affect a component governed by a different security authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.ALowAvailability impact: A successful attack can cause a limited loss.- Post-exploitation / living off the land
- No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
03
Patch and workaround
Operational remediation based on structured source evidence.
- Status
?
Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change. - Patch available
- Affected
- Cisco Identity Services Engine Software: 3.2 Patch 9, 3.1.0 p10, 3.2.0 p2, 3.3 Patch 11, 3.3.0, 3.4 Patch 3, 3.5.0, 3.4.0, 3.2.0 p4, 3.2.0 p3, 3.5 Patch 3, 3.2.0 p5, 3.3 Patch 2, 3.1.0 p3, 3.1.0 p7, 3.1.0 p4, 3.2 Patch 10, 3.1.0 p2, 3.1.0 p1, 3.4 Patch 6, 3.2.0 p6, 3.2.0 p7, 3.3 Patch 7, 3.1.0 p72, 3.4 Patch 4, 3.3 Patch 6, 3.3 Patch 10, 3.1.0, 3.3 Patch 4, 3.3 Patch 9, 3.1.0 p8, 3.1.0 p9, 3.3 Patch 1, 3.2.0, 3.1.0 p5, 3.3 Patch 12, 3.3 Patch 5, 3.1.0 p11, 3.4 Patch 2, 3.3 Patch 8, 3.1.0 p6, 3.2.0 p1, 3.4 Patch 5, 3.2 Patch 8, 3.5 Patch 1, 3.5 Patch 2, 3.3 Patch 3, 3.4 Patch 1
- Cisco ISE Passive Identity Connector: 3.4.0, 3.1.0, 3.3.0, 3.2.0, 3.5.0
- Action
- Apply the fixed release for the affected product branch as recorded by Canadian Centre for Cyber Security. Validate the exact product and build in the linked advisory before deployment.
- Workaround
- No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04
Evidence and provenance
Published 16 Sept 2026 · Last source change 17 Sept 2026, 11:39 UTC · CWE-290 · Authentication Bypass by Spoofing
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source FIRST · tracked since 2026-09-17
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2026-81107
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD awaiting enrichment
Core structured fields are present and their contributing authorities are shown above.
Material change intelligence
View recent updates ↗What changed after publication
- Affected versionsThe structured affected or fixed version information changed.Canadian Centre for Cyber Security ↗
- Before
- Cisco Identity Services Engine Software: 3.1.0, 3.1.0 p1, 3.1.0 p3, 3.1.0 p2, 3.2.0, 3.1.0 p4, 3.1.0 p5, 3.2.0 p1, 3.1.0 p6, 3.2.0 p2, 3.1.0 p7, 3.3.0, 3.2.0 p3, 3.2.0 p4, 3.1.0 p8, 3.2.0 p5, 3.2.0 p6, 3.1.0 p9, 3.3 Patch 2, 3.3 Patch 1, 3.3 Patch 3, 3.4.0, 3.2.0 p7, 3.3 Patch 4, 3.4 Patch 1, 3.1.0 p10, 3.3 Patch 5, 3.3 Patch 6, 3.4 Patch 2, 3.3 Patch 7, 3.4 Patch 3, 3.5.0, 3.4 Patch 4, 3.3 Patch 8, 3.2 Patch 8, 3.5 Patch 1, 3.3 Patch 9, 3.2 Patch 9, 3.4 Patch 5, 3.5 Patch 3, 3.5 Patch 2, 3.3 Patch 10, 3.3 Patch 11, 3.4 Patch 6, 3.2 Patch 10, 3.1.0 p72, 3.1.0 p11, 3.3 Patch 12; Cisco ISE Passive Identity Connector: 3.2.0, 3.1.0, 3.3.0, 3.4.0, 3.5.0 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
- After
- Cisco Identity Services Engine Software: 3.1.0, 3.1.0 p1, 3.1.0 p3, 3.1.0 p2, 3.2.0, 3.1.0 p4, 3.1.0 p5, 3.2.0 p1, 3.1.0 p6, 3.2.0 p2, 3.1.0 p7, 3.3.0, 3.2.0 p3, 3.2.0 p4, 3.1.0 p8, 3.2.0 p5, 3.2.0 p6, 3.1.0 p9, 3.3 Patch 2, 3.3 Patch 1, 3.3 Patch 3, 3.4.0, 3.2.0 p7, 3.3 Patch 4, 3.4 Patch 1, 3.1.0 p10, 3.3 Patch 5, 3.3 Patch 6, 3.4 Patch 2, 3.3 Patch 7, 3.4 Patch 3, 3.5.0, 3.4 Patch 4, 3.3 Patch 8, 3.2 Patch 8, 3.5 Patch 1, 3.3 Patch 9, 3.2 Patch 9, 3.4 Patch 5, 3.5 Patch 3, 3.5 Patch 2, 3.3 Patch 10, 3.3 Patch 11, 3.4 Patch 6, 3.2 Patch 10, 3.1.0 p72, 3.1.0 p11, 3.3 Patch 12; Cisco ISE Passive Identity Connector: 3.2.0, 3.1.0, 3.3.0, 3.4.0, 3.5.0 · Fixed: The Cyber Centre strongly recommends that organizations running Cisco ISE and ISE-PIC upgrade to the vendor-supported fixed software versions identified below. Affected product Affected releases Fixed releases Cisco Identity Services Engine (ISE) or ISE-PIC releases prior to 3.0 Migrate to a fixed release Cisco Identity Services Engine (ISE) or ISE-PIC release 3.1 3.1 Patch 12 Cisco Identity Services Engine (ISE) or ISE-PIC release 3.2 3.2 Patch 11 Cisco Identity Services Engine (ISE) or ISE-PIC release 3.3 3.3 Patch 12 Cisco Identity Services Engine (ISE) or ISE-PIC release 3.4 3.4 Patch 7 Cisco Identity Services Engine (ISE) or ISE-PIC release 3.5 3.5 Patch 4 The Cyber Centre also recommends organizations to: Apply vendor-provided security updates immediately. Cisco has released fixes for all three vulnerabilities. Prioritize remediation of CVE-2026-76460 due to confirmed in-the-wild exploitation. Review access logs for indicators of compromise (IoC), particularly suspicious usernames and unexpected API activity. Restrict access to management interfaces through access control lists (ACL), network segmentation, and trusted administration networks where feasible. If compromise is suspected, re-image affected nodes and restore from known-good backups, as attackers may obtain elevated privileges and remove evidence of exploitation. Monitor firewall, network, and authentication logs for anomalous activity associated with affected systems. Note: Organizations operating Common Criteria Footnote 10 evaluated configurations should review Cisco's advisory and apply the recommended updates in accordance with their change management and certification requirements. In addition, the Cyber Centre strongly recommends that organizations review and implement the Cyber Centre's Top 10 IT Security Actions Footnote 11 with an emphasis on the following topics: Consolidating, monitoring, and defending Internet gateways Patch operating systems and applications Harden operating systems and applications Isolate web-facing applications Should activity matching the content of this alert be discovered, recipients are encouraged to report via My Cyber Portal , or email contact@cyber.gc.ca .
- Remediation statusRemediation status changed from Awaiting fix to Patch available.Canadian Centre for Cyber Security ↗
- Before
- Awaiting fix
- After
- Patch available
- ENISA EUVD mappingEUVD-2026-81107 was added to the official ENISA EUVD mapping for this CVE.ENISA EUVD ↗
- Before
- not recorded
- After
- {"euvdId":"EUVD-2026-81107"}
- Catalogue recordCVE added to the BlackTree catalogue.CNA ↗
CVE published
Fixed release recorded from official guidance
Technical terms and abbreviations used in this report
- CVE
- Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
- CVSS
- Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
- EPSS
- Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
- CWE
- Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
- CNA
- CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
- CISA ADP
- Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
- NVD
- National Vulnerability Database: NIST's enrichment service for CVE records.
- CERT / CSIRT
- A computer security incident response team that publishes warnings or coordinates incident response.
- PoC
- Proof of concept: public material that demonstrates or helps reproduce exploitation.
- CSAF
- Common Security Advisory Framework: a machine-readable format for security advisories.
- LoTL
- Living off the land: abuse of legitimate tools or system functions during an attack.