# CVE-2020-3259 — Cisco Adaptive Security Appliance (ASA) Software

**CISA KEV** · **Ransomware**

> As of 2026-08-12, CVE-2020-3259 is a HIGH-severity vulnerability in Cisco Adaptive Security Appliance (ASA) Software, CVSS v3.1 7.5, EPSS 71.7% (99.4th percentile). It is listed in the CISA Known Exploited Vulnerabilities catalog (added 2024-02-15), with a US federal remediation deadline of 2024-03-07, and CISA links it to known ransomware campaigns. Threadlinqs Intelligence links 2 tracked threat campaigns to CVE-2020-3259, most recently “#StopRansomware: SafePay Ransomware (CISA AA26-293A) — Exploitation of Cisco ASA/FTD, Veeam B&R and SonicWall SonicOS”.

**Last updated:** 2026-08-12

## 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.

The record classifies CVE-2020-3259 under weakness class [CWE-200](https://intel.threadlinqs.com/cwe/CWE-200). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 2359 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 7.5 — HIGH (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **EPSS (FIRST):** 71.7% probability of exploitation in the next 30 days, higher than 99.4% of all scored CVEs
- **CISA KEV:** Listed since 2024-02-15, federal remediation deadline 2024-03-07 — used in known ransomware campaigns
- **Threadlinqs priority:** 10/10 — CISA lists it as used in ransomware, which Threadlinqs scores at the maximum
- **Published:** 2020-05-06, last modified 2026-08-12

## Is CVE-2020-3259 being exploited?

CISA added CVE-2020-3259 to the Known Exploited Vulnerabilities catalog on 2024-02-15, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2024-03-07 under BOD 22-01. CISA flags the vulnerability as one used in known ransomware campaigns. Weaponised exploit code for CVE-2020-3259 is publicly available. 1 public proof-of-concept repository is tracked for this identifier. It currently carries a trending score of 53 in the Threadlinqs vulnerability feed.

- [trickest/cve](https://github.com/trickest/cve/blob/main/2020/CVE-2020-3259.md) (trickest)

## Affected products and versions

- [Cisco](https://intel.threadlinqs.com/vendors/cisco): Adaptive Security Appliance (ASA) Software

## How to fix CVE-2020-3259

Because CVE-2020-3259 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2024-03-07. No vendor patch reference has been recorded for CVE-2020-3259 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2020-3259

2 tracked threats in the Threadlinqs corpus reference CVE-2020-3259, either in the campaign’s CVE list or as an indicator on the campaign record.

- [#StopRansomware: SafePay Ransomware (CISA AA26-293A) — Exploitation of Cisco ASA/FTD, Veeam B&R and SonicWall SonicOS](https://intel.threadlinqs.com/threat/TL-2026-3978) — CRITICAL · 2026-10-20
- [Healthcare Sector Ransomware Targeting and Expanding Attack Surface (Qilin, Akira, DragonForce, LockBit, The Gentlemen)](https://intel.threadlinqs.com/threat/TL-2026-3127) — HIGH · 2026-10-09

## Sources

Enriched from CVE.org, FIRST EPSS, CISA KEV, GitHub Security Advisories, public proof-of-concept repositories. Last verified by Threadlinqs on 2026-10-10.

**Vendor advisory and patch**

- [tools.cisco.com — vendor advisory](https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-info-disclose-9eJtycMB)

Canonical: https://intel.threadlinqs.com/cve/CVE-2020-3259
Full detection coverage and IOCs for threats exploiting CVE-2020-3259 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp