Cisco ASA and FTD Information Disclosure Vulnerability
Cisco — Cisco Adaptive Security Appliance (ASA) Software
A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to retrieve memory contents on an affected device, which could lead to the disclosure of confidential information. The vulnerability is due to a buffer tracking issue when the software parses invalid URLs that are requested from the web services interface. An attacker could exploit this vulnerability by sending a crafted GET request to the web services interface. A successful exploit could allow the attacker to retrieve memory contents, which could lead to the disclosure of confidential information. Note: This vulnerability affects only specific AnyConnect and WebVPN configurations. For more information, see the Vulnerable Products section.
7.5
71.8%
Vector breakdown
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- Published
- May 6, 2020
- Modified
- Oct 21, 2025
- Added to KEV
- Feb 15, 2024
- Federal patch due
- Mar 7, 2024
CISA required action
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Weakness classification
Proof-of-concept & exploitation references
Weaponization
Public repositories whose name or description references CVE-2020-3259, found via a live GitHub search at request time. These are community-sourced signals, not a verified working exploit - cross-check each one before relying on it, and treat higher star counts and recent activity as (weak) corroboration, not proof.
No public GitHub repositories referencing CVE-2020-3259 were found at last check. Absence here is not proof no exploit exists - see the references below for vendor advisories and write-ups.
References
Frequently asked questions
What is CVE-2020-3259?
A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to retrieve memory contents on an affected device, which could lead to the disclosure of confidential information. The vulnerability is due to a buffer tracking issue when the software parses invalid URLs that are requested from the web services interface. An attacker could exploit this vulnerability by sending a crafted GET request to the web services interface. A successful exploit could allow the attacker to retrieve memory contents, which could lead to the disclosure of confidential information. Note: This vulnerability affects only specific AnyConnect and WebVPN configurations. For more information, see the Vulnerable Products section.
How severe is CVE-2020-3259?
CVE-2020-3259 has a CVSS base score of 7.5 out of 10 (CVSS 3.0).
Is CVE-2020-3259 actively exploited in the wild?
Yes. CVE-2020-3259 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added Feb 15, 2024, meaning CISA has confirmed evidence of active exploitation. It is also flagged as used in ransomware campaigns.
What is the EPSS score for CVE-2020-3259?
71.8% - meaning FIRST.org's EPSS model estimates a 71.8% probability this vulnerability will be exploited in the wild within 30 days (99% percentile among all scored CVEs).
What type of vulnerability is CVE-2020-3259?
CVE-2020-3259 is classified under CWE-200.
Cross-checked against
Impactr finds and proves whether CVE-2020-3259 - or flaws like it - are actually reachable in your own web apps and APIs, with a reproducible exploit as evidence.
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