CVE-2020-3259

What is affected

Vendor	Cisco
Product	Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD)
Weakness	CWE-200

The 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.

Required action

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

US federal civilian agencies were required to act by 7 March 2024 under BOD 22-01. The deadline is a compliance date, not a measure of severity — it says nothing about how dangerous the flaw is to anyone else.

Ransomware

CISA records this vulnerability as having been used in ransomware campaigns. That is a confirmed observation, not an assessment of likelihood.

Where this comes from

Every field on this page is taken from the CISA Known Exploited Vulnerabilities catalog, last synced 11 Nov 2026, 21:30. Nothing here is our own assessment. For the technical scoring, see the NVD record below.

NVD record ↗ CVE.org record ↗