Quick answers
- Is CVE-2026-76439 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-76439 being exploited in the wild.
- How severe is CVE-2026-76439?
- Medium severity, with a CVSS score of 5.3, published 16 September 2026.
- Which products and versions are affected?
- Cisco Identity Services Engine.
- Is there a fix for CVE-2026-76439?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-76439 attacked?
- It is attacked over the network.
- Am I affected by CVE-2026-76439?
- Check whether you run Cisco Identity Services Engine. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
CVE-2026-76439 is an authentication bypass vulnerability in the endpoint posture status reporting functionality exposed through the Cisco ISE guest portal web application. The vulnerability stems from insufficient authentication controls on an internal interface, allowing an unauthenticated, remote attacker to submit forged posture status events. The attack vector is network-based with no authentication or user interaction required (CVSS vector: AV:N/AC:L/PR:N/UI:N). A successful exploit allows manipulation of endpoint posture status on the affected system, which could lead to unauthorized access or policy bypass. Cisco has released software patches to address this issue; no workarounds are available.
Affected products
- Cisco Identity Services Engine
Timeline
- 2026-09-16: disclosed