How severe is CVE-2026-76439?

CVE-2026-76439 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2026-76439 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-76439?

CVE-2026-76439 primarily affects Cisco Identity Services Engine. In total, 42 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-76439?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2026-76439 published?

CVE-2026-76439 was published on 2026-09-16 and last updated on 2026-09-28.

CVE-2026-76439

CVE-2026-76439 is a medium-severity vulnerability in Cisco Identity Services Engine with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-306.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
EPSS exploit prediction: 0% (23rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-306
Affected product: Cisco Identity Services Engine
Published: 2026-09-16
Last modified: 2026-09-28

Description

A vulnerability in the endpoint posture status reporting functionality of the guest portal web application of Cisco ISE could allow an unauthenticated, remote attacker to submit forged posture status events into the endpoint posture pipeline. This vulnerability is due to insufficient authentication on an internal interface that is exposed through the guest portal. An attacker could exploit this vulnerability by sending a crafted request to an affected system. A successful exploit could allow the attacker to manipulate the posture status on the affected system.

Frequently asked questions

What is CVE-2026-76439?: A vulnerability in the endpoint posture status reporting functionality of the guest portal web application of Cisco ISE could allow an unauthenticated, remote attacker to submit forged posture status events into the endpoint posture pipeline. This vulnerability is due to insufficient authentication on an internal interface that is exposed through the guest portal. An attacker could exploit this vulnerability by sending a crafted request to an affected system. A successful exploit could allow the attacker to manipulate the posture status on the affected system.
How severe is CVE-2026-76439?: CVE-2026-76439 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2026-76439 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-76439?: CVE-2026-76439 primarily affects Cisco Identity Services Engine. In total, 42 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-76439?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-76439 published?: CVE-2026-76439 was published on 2026-09-16 and last updated on 2026-09-28.

References

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ise-multiauth-bypass-sgD2HbL4

Affected products (42)

cpe:2.3:a:cisco:identity_services_engine:*:*:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.3.0:patch1:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.3.0:patch10:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.3.0:patch11:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.3.0:patch2:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.3.0:patch3:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.3.0:patch4:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.3.0:patch5:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.3.0:patch6:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.3.0:patch7:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.3.0:patch8:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.3.0:patch9:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.4.0:-:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.4.0:patch1:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.4.0:patch2:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.4.0:patch3:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.4.0:patch4:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.4.0:patch5:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.4.0:patch6:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.5.0:-:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.5.0:patch1:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.5.0:patch2:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine:3.5.0:patch3:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine_passive_identity_connector:*:*:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine_passive_identity_connector:3.3.0:patch1:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine_passive_identity_connector:3.3.0:patch10:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine_passive_identity_connector:3.3.0:patch11:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine_passive_identity_connector:3.3.0:patch2:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine_passive_identity_connector:3.3.0:patch3:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine_passive_identity_connector:3.3.0:patch4:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine_passive_identity_connector:3.3.0:patch5:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine_passive_identity_connector:3.3.0:patch6:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine_passive_identity_connector:3.3.0:patch7:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine_passive_identity_connector:3.3.0:patch8:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine_passive_identity_connector:3.3.0:patch9:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine_passive_identity_connector:3.4.0:-:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine_passive_identity_connector:3.4.0:patch1:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine_passive_identity_connector:3.4.0:patch2:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine_passive_identity_connector:3.4.0:patch3:*:*:*:*:*:*
cpe:2.3:a:cisco:identity_services_engine_passive_identity_connector:3.4.0:patch4:*:*:*:*:*:*

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