CVE-2021-22985Network attack vector

Authenticated service interruption via VPN memory exhaustion

Published Feb 12, 2021 · Updated Aug 3, 2024

Uncontrolled resource consumption in F5 BIG-IP APM 16.0.x before 16.0.1.1 allows remote authenticated users to interrupt service via VPN traffic. Under certain conditions, TMM fails to bound memory consumption while processing attacker-controlled VPN traffic, allowing that traffic to exhaust memory. A valid VPN session is required, and the documented consequence is APM denial of service rather than data disclosure or modification.

CVSS severity7.5
High
EPSS probability1.01%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncontrolled resource consumption in F5 BIG-IP APM 16.0.x before 16.0.1.1 allows remote authenticated users to interrupt service via VPN traffic. Under certain conditions, TMM fails to bound memory consumption while processing attacker-controlled VPN traffic, allowing that traffic to exhaust memory. A valid VPN session is required, and the documented consequence is APM denial of service rather than data disclosure or modification.

The record

CVE
CVE-2021-22985
Published
Feb 12, 2021
Updated
Aug 3, 2024
Vendor
F5 Networks
Product
BIG-IP Access Policy Manager
Classifications
CWE-400, T1499.003
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 12, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=16.0.x before 16.0.1.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

F5 Networks · BIG-IP Access Policy Managerversion=16.0.x before 16.0.1.1

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.8NIST NVDAV:N/AC:L/Au:N/C:N/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-400Uncontrolled Resource Consumption
T1499.003Application Exhaustion Flood

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

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Your stack

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