CVE-2026-20009 Vulnerability Analysis & Exploit Details

CVE-2026-20009
Vulnerability Scoring

5.3
/10
Significant Risk

Security assessments indicate that CVE-2026-20009 presents a notable risk, potentially requiring prompt mitigation.

Attack Complexity Details

  • Attack Complexity: Low
    Exploits can be performed without significant complexity or special conditions.
  • Attack Vector: Network
    Vulnerability is exploitable over a network without physical access.
  • Privileges Required: None
    No privileges are required for exploitation.
  • Scope: Unchanged
    Exploit remains within the originally vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2026-20009 Details

Status: Analyzed

Last updated: 🕗 16 Apr 2026, 20:13 UTC
Originally published on: 🕕 04 Mar 2026, 18:16 UTC

Time between publication and last update: 43 days

CVSS Release: version 3

CVSS3 Source

psirt@cisco.com

CVSS3 Type

Primary

CVSS3 Vector

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

CVE-2026-20009 Vulnerability Summary

CVE-2026-20009: A vulnerability in the implementation of the proprietary SSH stack with SSH key-based authentication in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software could allow an unauthenticated, remote attacker to log in to a Cisco Secure Firewall ASA device and execute commands as a specific user. This vulnerability is due to insufficient validation of user input during the SSH authentication phase. An attacker could exploit this vulnerability by submitting crafted input during SSH authentication to an affected device. A successful exploit could allow the attacker to log in to the device as a specific user without the private SSH key of that user. To exploit this vulnerability, the attacker must possess a valid username and the associated public key. The private key is not required. Notes: Exploitation of this vulnerability does not provide the attacker with root access. The authentication, authorization, and accounting (AAA) configuration command auto-enable is not affected by this vulnerability.  

Assessing the Risk of CVE-2026-20009

Access Complexity Graph

The exploitability of CVE-2026-20009 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2026-20009

With low attack complexity and no required privileges, CVE-2026-20009 is an easy target for cybercriminals. Organizations should prioritize immediate mitigation measures to prevent unauthorized access and data breaches.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2026-20009, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2026-20009, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: Low
    CVE-2026-20009 could lead to minor leaks of non-critical information without major privacy breaches.
  • Integrity: None
    CVE-2026-20009 poses no threat to data integrity.
  • Availability: None
    CVE-2026-20009 does not impact system availability.

CVE-2026-20009 References

External References

CWE Common Weakness Enumeration

CWE-138

CAPEC Common Attack Pattern Enumeration and Classification

  • HTTP Request Splitting CAPEC-105 An adversary abuses the flexibility and discrepancies in the parsing and interpretation of HTTP Request messages by different intermediary HTTP agents (e.g., load balancer, reverse proxy, web caching proxies, application firewalls, etc.) to split a single HTTP request into multiple unauthorized and malicious HTTP requests to a back-end HTTP agent (e.g., web server). See CanPrecede relationships for possible consequences.
  • Command Delimiters CAPEC-15 An attack of this type exploits a programs' vulnerabilities that allows an attacker's commands to be concatenated onto a legitimate command with the intent of targeting other resources such as the file system or database. The system that uses a filter or denylist input validation, as opposed to allowlist validation is vulnerable to an attacker who predicts delimiters (or combinations of delimiters) not present in the filter or denylist. As with other injection attacks, the attacker uses the command delimiter payload as an entry point to tunnel through the application and activate additional attacks through SQL queries, shell commands, network scanning, and so on.
  • HTTP Response Splitting CAPEC-34 An adversary manipulates and injects malicious content, in the form of secret unauthorized HTTP responses, into a single HTTP response from a vulnerable or compromised back-end HTTP agent (e.g., web server) or into an already spoofed HTTP response from an adversary controlled domain/site. See CanPrecede relationships for possible consequences.

Vulnerable Configurations

  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.7:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.7:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.9:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.9:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.10:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.10:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.11:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.11:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.13:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.13:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.15:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.15:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.20:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.20:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.30:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.30:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.33:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.33:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.39:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.39:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.45:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.17.1.45:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.1:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.1:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.1.3:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.1.3:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.2:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.2:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.2.5:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.2.5:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.2.7:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.2.7:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.2.8:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.2.8:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.3:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.3:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.3.39:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.3.39:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.3.46:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.3.46:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.3.53:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.3.53:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.3.55:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.3.55:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.3.56:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.3.56:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.4:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.4:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.4.5:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.4.5:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.4.8:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.4.8:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.4.22:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.4.22:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.4.24:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.4.24:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.4.29:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.4.29:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.4.34:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.4.34:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.4.40:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.4.40:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.4.47:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.4.47:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.4.57:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.4.57:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.4.67:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.18.4.67:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1.5:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1.5:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1.9:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1.9:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1.12:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1.12:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1.18:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1.18:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1.22:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1.22:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1.24:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1.24:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1.27:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1.27:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1.28:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1.28:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1.31:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1.31:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1.37:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1.37:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1.42:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.19.1.42:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.1:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.1:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.1.5:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.1.5:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.2:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.2:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.2.10:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.2.10:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.2.21:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.2.21:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.2.22:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.2.22:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.3:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.3:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.3.4:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.3.4:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.3.7:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.3.7:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.3.16:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.20.3.16:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.22.1.1:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.22.1.1:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.22.1.3:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.22.1.3:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.22.2:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.22.2:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:adaptive_security_appliance_software:9.23.1.3:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:adaptive_security_appliance_software:9.23.1.3:*:*:*:*:*:*:*

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