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CVE-2020-3259

KEVRansomware UseCisco 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.

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.

CVSS 3.1 vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
PublishedMay 6, 2020
Last modifiedAug 12, 2026
Added to KEVFeb 15, 2024
Remediation dueMar 7, 2024
    85
    Risk assessment · Critical

    Actively exploited and used by ransomware crews. Patch immediately.

    Exploitation
    Confirmed in the wild (CISA KEV)
    Federal remediation deadline
    Overdue by 964 days
    Ransomware
    Used in known ransomware campaigns
    CVSS
    7.5 HIGH
    EPSS (30-day exploit probability)
    71.5% · top 1% of all CVEs
    Weakness
    CWE-200
    Attack vector
    Network, remotely reachable
    Preconditions
    No privileges and no user interaction
    1. 1.Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
    2. 2.Treat as emergency change: patch or isolate internet-facing instances first.
    3. 3.Review exposure: confirm which instances are reachable from the internet and restrict access until patched.
    4. 4.Hunt for compromise: review logs for the disclosure window, not just from the patch date.
    5. 5.Verify offline/immutable backups and segment the affected systems. This flaw is used for ransomware initial access.

    Assessment is derived automatically from the live signals above; verify against your own asset inventory.