CVE-2020-3259
HIGHCISA KEVEPSS 99th pctlDescription
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 to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Exploit Intelligence
Very high risk: more likely to be exploited than 99% of all known CVEs.
Cisco ASA and FTD Information Disclosure Vulnerability
Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) contain an information disclosure vulnerability. An attacker could retrieve memory contents on an affected device, which could lead to the disclosure of confidential information due to a buffer tracking issue when the software parses invalid URLs that are requested from the web services interface. This vulnerability affects only specific AnyConnect and WebVPN configurations.
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Remediation due: 2024-03-07
Associated with ransomware campaigns
References
Related Vulnerabilities
Other CWE-200 (Information Exposure) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2024-24919 | High | 8.6 | 100% | KEV + Ransom | - |
| CVE-2020-14181 | Medium | 5.3 | 100% | - | Fix |
| CVE-2021-34429 | Medium | 5.3 | 99% | - | Fix |
| CVE-2018-11409 | Medium | 5.3 | 98% | - | - |
| CVE-2021-41277 | Critical | 10.0 | 97% | KEV | - |
| CVE-2016-2183 | High | 7.5 | 96% | - | Fix |
Common questions
How do I fix CVE-2020-3259?
Published advisories record a fix for 2 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.
Is CVE-2020-3259 being actively exploited?
Yes. CVE-2020-3259 is listed in the CISA Known Exploited Vulnerabilities catalog, which means exploitation has been observed in the wild. CISA has also linked it to known ransomware campaigns. US federal agencies were required to remediate it by 2024-03-07. Treat it as a priority whatever its CVSS score says.
How severe is CVE-2020-3259?
CVE-2020-3259 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2020-3259 affect?
Published advisories record a fix for adaptive security appliance software (NVD), firepower threat defense (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-10-28.