VulnerabilityPublished 4 Mar 2026

CVE-2026-20069: Cisco Secure Firewall Adaptive Security Appliance (ASA) Software · HTTP Request/Response Smuggling

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

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Not known to be exploited · CVSS 4.3 Medium.

Data as of 29 Oct 2026, 19:04 UTC

CVSS 3.1 base score

4.3Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 21% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

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

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: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

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 29 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 – 9.23.1.7 151 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

Apply official Cisco patches and updates as soon as they become available for the affected ASA and FTD software versions.
If VPN web services endpoints are not required, disable them to eliminate the attack surface.
Implement strict input validation and sanitization on web services endpoints to prevent injection of malicious HTTP requests.
Deploy web filtering and URL reputation services to block access to known malicious or suspicious websites that could host exploit payloads.
Educate users about the risks of clicking unknown or suspicious links, especially when accessing VPN services.
Monitor firewall logs and web service access patterns for anomalous or suspicious HTTP requests indicative of exploitation attempts.
Use Content Security Policy (CSP) headers and other browser security controls to mitigate the impact of reflected XSS attacks on users.
Consider network segmentation to limit exposure of VPN web services to only trusted networks or IP ranges.
Regularly audit and review firewall configurations to ensure minimal exposure of unnecessary web services.
Coordinate with Cisco support and subscribe to security advisories for timely information on patches and mitigations.

Description

A vulnerability in the VPN web services component of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to conduct browser-based attacks against users of an affected device. This vulnerability is due to improper validation of HTTP requests. An attacker could exploit this vulnerability by persuading a user to visit a website that is designed to pass malicious HTTP requests to a device that is running Cisco Secure Firewall ASA Software or Cisco Secure FTD Software and has web services endpoints supporting VPN features enabled. A successful exploit could allow the attacker to reflect malicious input from the affected device to the browser that is in use and conduct browser-based attacks, including cross-site scripting (XSS) attacks. The attacker is not able to directly impact the affected device.

Impact

The primary impact of CVE-2026-20069 is on the integrity of user sessions and the security of users' browsers rather than the firewall devices themselves. Attackers can conduct reflected XSS attacks by leveraging the vulnerable firewall as a relay, potentially stealing session cookies, executing malicious scripts, or performing other browser-based exploits against users. This can lead to credential theft, session hijacking, or further compromise of user endpoints. Organizations relying on Cisco ASA and FTD devices for VPN access and perimeter security may see an increased risk of targeted phishing or drive-by attacks exploiting this vulnerability. While the firewall device's confidentiality and availability remain intact, the indirect compromise of user endpoints can lead to broader network infiltration or data breaches. The wide range of affected versions and the prevalence of Cisco firewalls in enterprise, government, and critical infrastructure sectors globally amplify the potential impact. However, the requirement for user interaction and no direct device compromise limit the scope to user-targeted attacks rather than mass exploitation or automated worming.

References

sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-desync-n5AVzEQw (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 11 Mar 2026, 20:19 UTC

Technical details

References

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