CVE-2022-20737Network attack vector

Authenticated memory disclosure or reload via HTTP parsing

Published May 3, 2022 · Updated Nov 6, 2024

Heap buffer overflow in Cisco ASA Software's Clientless SSL VPN allows remote authenticated users to read process memory or reload the device. The HTTP authentication handler performs insufficient bounds checking while parsing specific authentication messages, causing a heap overwrite. Exploitation requires Clientless SSL VPN to be configured and an attacker-controlled web server to be reachable through the portal; success exposes process-memory bytes or forces a device reload.

CVSS severity8.5
High
EPSS probability1.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Heap buffer overflow in Cisco ASA Software's Clientless SSL VPN allows remote authenticated users to read process memory or reload the device. The HTTP authentication handler performs insufficient bounds checking while parsing specific authentication messages, causing a heap overwrite. Exploitation requires Clientless SSL VPN to be configured and an attacker-controlled web server to be reachable through the portal; success exposes process-memory bytes or forces a device reload.

The record

CVE
CVE-2022-20737
Published
May 3, 2022
Updated
Nov 6, 2024
Vendor
ClamAV
Product
Cisco Adaptive Security Appliance (ASA) Software
Classifications
CWE-787, CWE-122, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 3, 2022CVE publishedPublication date reported by the CVE source.
  2. Nov 6, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

ClamAV · Cisco Adaptive Security Appliance (ASA) Softwareversion=n/a

Published CVSS scores

8.5Cisco Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:H
7.1NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H
7.0NIST National Vulnerability DatabaseAV:N/AC:M/Au:S/C:P/I:N/A:C

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
CWE-122Heap-based Buffer Overflow
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo