CVE-2016-6431

CVE-2016-6431 is a high-severity vulnerability in Cisco Adaptive Security Appliance Software with a CVSS 3.x base score of 7.5. 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-20.

Key facts

Description

A vulnerability in the local Certificate Authority (CA) feature of Cisco ASA Software before 9.6(1.5) could allow an unauthenticated, remote attacker to cause a reload of the affected system. The vulnerability is due to improper handling of crafted packets during the enrollment operation. An attacker could exploit this vulnerability by sending a crafted enrollment request to the affected system. An exploit could allow the attacker to cause the reload of the affected system. Note: Only HTTPS packets directed to the Cisco ASA interface, where the local CA is allowing user enrollment, can be used to trigger this vulnerability. This vulnerability affects systems configured in routed firewall mode and in single or multiple context mode.

Frequently asked questions

What is CVE-2016-6431?
A vulnerability in the local Certificate Authority (CA) feature of Cisco ASA Software before 9.6(1.5) could allow an unauthenticated, remote attacker to cause a reload of the affected system. The vulnerability is due to improper handling of crafted packets during the enrollment operation. An attacker could exploit this vulnerability by sending a crafted enrollment request to the affected system. An exploit could allow the attacker to cause the reload of the affected system. Note: Only HTTPS packets directed to the Cisco ASA interface, where the local CA is allowing user enrollment, can be used to trigger this vulnerability. This vulnerability affects systems configured in routed firewall mode and in single or multiple context mode.
How severe is CVE-2016-6431?
CVE-2016-6431 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2016-6431 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (83rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-6431?
CVE-2016-6431 primarily affects Cisco Adaptive Security Appliance Software. In total, 206 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2016-6431?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2016-6431 published?
CVE-2016-6431 was published on 2016-10-27 and last updated on 2026-06-17.

References

Affected products (206)

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