CVE-2021-23045Network attack vector

Unauthenticated TMM crash via undisclosed SCTP requests

Published Sep 14, 2021 · Updated Aug 3, 2024

Improper input validation in affected F5 BIG-IP releases allows remote attackers to crash TMM via undisclosed SCTP requests. The flaw lies in TMM request handling for a virtual server using an SCTP profile with multiple paths; F5 has not published the exact validation error. The multipath SCTP profile is required, and a successful request terminates TMM, interrupting traffic handled by that process.

CVSS severity7.5
High
EPSS probability0.93%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in affected F5 BIG-IP releases allows remote attackers to crash TMM via undisclosed SCTP requests. The flaw lies in TMM request handling for a virtual server using an SCTP profile with multiple paths; F5 has not published the exact validation error. The multipath SCTP profile is required, and a successful request terminates TMM, interrupting traffic handled by that process.

The record

CVE
CVE-2021-23045
Published
Sep 14, 2021
Updated
Aug 3, 2024
Vendor
F5 Networks
Product
BIG-IP
Classifications
CWE-20, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 14, 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 16.0.1.2, 15.1.x before 15.1.3.1, 14.1.x before 14.1.4.3, 13.1.x before 13.1.4.1, and all versions of 12.1.x

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

F5 Networks · BIG-IPversion=16.0.x before 16.0.1.2, 15.1.x before 15.1.3.1, 14.1.x before 14.1.4.3, 13.1.x before 13.1.4.1, and all versions of 12.1.x

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:N/A:P
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1499Endpoint Denial of Service

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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