CVE-2023-20269: Cisco Adaptive Security Appliance and Firepower Threat Defense Unauthorized Access Vulnerability

Is it exploited?

Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 13 Sep 2023, 7 days after the CVE record was published.

How likely is exploitation in the next 30 days?

26.6%

EPSS score, percentile 98 of all scored records

How severe?

5.0 Medium

CVSS v3.1 base score, given by the CNA

What should I do?

CISA deadline 4 Oct 2023. Apply mitigations per vendor instructions for group-lock and vpn-simultaneous-logins or discontinue use of the product for unsupported devices.

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected

• 9.8.1
• 9.8.1.5
• 9.8.1.7
• 9.8.2
• 9.8.2.8
• 9.8.2.14

and 18 more in the table below

Versions by product

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

What to do

CISA due date for this action: 4 October 2023.

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

Linked from CISA's catalog entry

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ravpn-auth-8LyfCkeC
• https://nvd.nist.gov/vuln/detail/CVE-2023-20269

Affected products and versions

As listed in the CVE record.

And 158 more version entries in the CVE record.

And 64 more version entries in the CVE record.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

About this vulnerability

Cisco Adaptive Security Appliance and Firepower Threat Defense contain an unauthorized access vulnerability that could allow an unauthenticated, remote attacker to conduct a brute force attack in an attempt to identify valid username and password combinations or establish a clientless SSL VPN session with an unauthorized user.

Summary: CISA's KEV catalog, as of 28 Oct 2026.

• CISA added CVE-2023-20269 to its Known Exploited Vulnerabilities (KEV) catalog on 13 Sep 2023.
• CISA marks it as known to be used in ransomware campaigns.
• The due date CISA sets for the required action is 4 Oct 2023.
• The CVE record was published on 6 Sep 2023, 7 days before it was added to KEV.
• The CVE record carries a CVSS v3.1 base score of 5.0 (Medium), given by its CNA.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 26.6% (percentile 98), as of 28 Oct 2026.
• CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact partial.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.

Description

A vulnerability in the remote access VPN feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to conduct a brute force attack in an attempt to identify valid username and password combinations or an authenticated, remote attacker to establish a clientless SSL VPN session with an unauthorized user. This vulnerability is due to improper separation of authentication, authorization, and accounting (AAA) between the remote access VPN feature and the HTTPS management and site-to-site VPN features. An attacker could exploit this vulnerability by specifying a default connection profile/tunnel group while conducting a brute force attack or while establishing a clientless SSL VPN session using valid credentials. A successful exploit could allow the attacker to achieve one or both of the following: Identify valid credentials that could then be used to establish an unauthorized remote access VPN session. Establish a clientless SSL VPN session (only when running Cisco ASA Software Release 9.16 or earlier). Notes: Establishing a client-based remote access VPN tunnel is not possible as these default connection profiles/tunnel groups do not and cannot have an IP address pool configured. This vulnerability does not allow an attacker to bypass authentication. To successfully establish a remote access VPN session, valid credentials are required, including a valid second factor if multi-factor authentication (MFA) is configured. Cisco will release software updates that address this vulnerability. There are workarounds that address this vulnerability.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

Weakness

• CWE-288

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.

Timeline

References

• cisco-sa-asaftd-ravpn-auth-8LyfCkeC

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