CVE-2023-20269
Authentication Bypass Using an Alternate Path or Channel
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N
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.
Official description from the CVE record, published by cisco. Copyright © 1999-2026 The MITRE Corporation. See /security/cve/legal for the CVE license. View the record on cve.org
Key data
CVSS 3.1 Medium 5.0
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N
Attack vector: Network
The vulnerable component can be reached over a network, possibly from the Internet.
Attack complexity: Low
No special conditions are needed. The attack can be repeated at will.
Privileges required: Low
A basic user account is needed.
User interaction: None
No action from any user is needed.
Scope: Changed
The impact can reach other components beyond the vulnerable one.
Confidentiality impact: None
No effect on the secrecy of data.
Integrity impact: Low
Limited effect on the trustworthiness of data.
Availability impact: None
No effect on availability.
| Metric | Value | What it means |
|---|---|---|
| Attack vector | Network | The vulnerable component can be reached over a network, possibly from the Internet. |
| Attack complexity | Low | No special conditions are needed. The attack can be repeated at will. |
| Privileges required | Low | A basic user account is needed. |
| User interaction | None | No action from any user is needed. |
| Scope | Changed | The impact can reach other components beyond the vulnerable one. |
| Confidentiality impact | None | No effect on the secrecy of data. |
| Integrity impact | Low | Limited effect on the trustworthiness of data. |
| Availability impact | None | No effect on availability. |
CVSS is owned and managed by FIRST.Org, Inc. (FIRST) and is used by permission. Each CVSS score on this site is shown together with its vector string, as published in the CVE record by the source named next to it. Learn more at first.org/cvss.
EPSS
- Score
- 0.26623 (26.6% probability)
- Percentile
- 98.0%
- Scores of
- Nov 10, 2026
- Model
- v2026.06.15
CISA Known Exploited Vulnerabilities
- Name in the catalog
- Cisco Adaptive Security Appliance and Firepower Threat Defense Unauthorized Access Vulnerability
- Added to the catalog
- Sep 13, 2023
- Federal due date
- Oct 4, 2023
- Ransomware campaigns
- Known use
CISA assessment as of Sep 7, 2023
- Exploitation
- Recorded by CISA as active
- Automatable
- no
- Technical impact
- partial
Weakness (CWE)
- CWE-288Authentication Bypass Using an Alternate Path or Channel
Affected products
Cisco Adaptive Security Appliance (ASA) Software
- affected: 9.8.1
- affected: 9.8.1.5
- affected: 9.8.1.7
- affected: 9.8.2
- affected: 9.8.2.8
- affected: 9.8.2.14
- affected: 9.8.2.15
- affected: 9.8.2.17
- affected: 9.8.2.20
- affected: 9.8.2.24
- affected: 9.8.2.26
- affected: 9.8.2.28
- affected: 9.8.2.33
- affected: 9.8.2.35
- affected: 9.8.2.38
- affected: 9.8.3.8
- affected: 9.8.3.11
- affected: 9.8.3.14
- affected: 9.8.3.16
- affected: 9.8.3.18
- affected: 9.8.3.21
- affected: 9.8.3
- affected: 9.8.3.26
- affected: 9.8.3.29
- affected: 9.8.4
- and 145 more
Cisco Firepower Threat Defense Software
- affected: 6.2.3
- affected: 6.2.3.1
- affected: 6.2.3.2
- affected: 6.2.3.3
- affected: 6.2.3.4
- affected: 6.2.3.5
- affected: 6.2.3.6
- affected: 6.2.3.7
- affected: 6.2.3.8
- affected: 6.2.3.10
- affected: 6.2.3.11
- affected: 6.2.3.9
- affected: 6.2.3.12
- affected: 6.2.3.13
- affected: 6.2.3.14
- affected: 6.2.3.15
- affected: 6.2.3.16
- affected: 6.2.3.17
- affected: 6.2.3.18
- affected: 6.6.0
- affected: 6.6.0.1
- affected: 6.6.1
- affected: 6.6.3
- affected: 6.6.4
- affected: 6.6.5
- and 51 more
References
- cisco-sa-asaftd-ravpn-auth-8LyfCkeC (sec.cloudapps.cisco.com)
Timeline
- ID reserved
- Record published
- Added to CISA KEV
- Record last updated
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About CubePath
Data from the CVE Program (MITRE), CISA KEV and FIRST EPSS. CVSS is owned by FIRST and used by permission. Not affiliated with or endorsed by MITRE, CISA or FIRST. Data as of Nov 10, 2026, 19:24 UTC. Sources and licenses