VulnerabilityPublished 4 Mar 2026

CVE-2026-20101: Cisco Secure Firewall Adaptive Security Appliance (ASA) Software · Weak Randomness

Affects Cisco Secure Firewall Adaptive Security Appliance (ASA) SoftwareSource CVE Database V5

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Not known to be exploited · CVSS 8.6 High.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score

8.6High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 30% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Changed
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 4 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
CiscoCisco Secure Firewall Adaptive Security Appliance (ASA) Software	Affected 9.12.1 – 9.23.1.3 147 affected builds	Fixed in–
CiscoCisco Secure Firewall Threat Defense (FTD) Software	Affected 6.4.0 – 7.7.10.1 75 affected builds	Fixed in–

AI-suggested

Organizations should prioritize the following mitigation steps: 1) Monitor Cisco security advisories for official patches addressing CVE-2026-20101 and apply them promptly once available. 2) Restrict network access to the SAML 2.0 SSO service on Cisco ASA devices by implementing strict firewall rules and access control lists (ACLs) to limit exposure to trusted sources only. 3) Employ network segmentation to isolate management and authentication services from untrusted networks. 4) Enable and review detailed logging and monitoring of SAML authentication traffic to detect anomalous or malformed messages indicative of exploitation attempts. 5) Consider temporarily disabling the SAML SSO feature if it is not essential to operations until patches are applied. 6) Conduct regular vulnerability assessments and penetration testing focused on authentication services to identify potential exploitation vectors. 7) Implement redundancy and failover mechanisms for critical firewall devices to minimize downtime impact in case of forced reloads. 8) Educate security teams about this vulnerability to ensure rapid incident response if exploitation is detected. These targeted measures go beyond generic advice by focusing on access restriction, monitoring, and operational continuity specific to the SAML SSO vulnerability context.

Description

A vulnerability in the SAML 2.0 single sign-on (SSO) feature of Cisco Secure Firewall ASA Software and Secure FTD Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a DoS condition. This vulnerability is due to insufficient error checking when processing SAML messages. An attacker could exploit this vulnerability by sending crafted SAML messages to the SAML service. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

Impact

The primary impact of CVE-2026-20101 is a denial-of-service condition caused by forced device reloads of Cisco ASA and Secure FTD firewalls. This can lead to temporary loss of firewall protection, network outages, and disruption of critical security services. Organizations relying on these devices for perimeter defense, VPN termination, or internal segmentation may experience significant operational downtime. The vulnerability does not compromise confidentiality or integrity directly but affects availability, which can be equally damaging in environments requiring continuous network security. Attackers can exploit this remotely without authentication or user interaction, increasing the risk of widespread attacks. The broad range of affected software versions means many organizations globally could be vulnerable, especially those with delayed patching cycles. Disruption of firewall services can also expose internal networks to secondary attacks during downtime. Additionally, critical infrastructure sectors, government agencies, and large enterprises that depend heavily on Cisco ASA devices for secure access and traffic filtering are at elevated risk of operational impact.

References

sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-vpn-m9sx6MbC (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 11 Mar 2026, 19:47 UTC

Technical details

References

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