CVE-2023-22839Network attack vector

Service interruption via NULL pointer dereference

Published Feb 1, 2023 · Updated Mar 26, 2025

NULL pointer dereference in F5 BIG-IP allows remote attackers to terminate TMM by sending undisclosed requests to affected virtual servers. TMM dereferences a null pointer while processing the requests, but F5 has not disclosed the request format or exact code path. Exposure requires a DNS profile with Rapid Response Mode enabled on a virtual server that also uses hardware SYN cookies; successful requests interrupt traffic processing.

CVSS severity7.5
High
EPSS probability0.63%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in F5 BIG-IP allows remote attackers to terminate TMM by sending undisclosed requests to affected virtual servers. TMM dereferences a null pointer while processing the requests, but F5 has not disclosed the request format or exact code path. Exposure requires a DNS profile with Rapid Response Mode enabled on a virtual server that also uses hardware SYN cookies; successful requests interrupt traffic processing.

The record

CVE
CVE-2023-22839
Published
Feb 1, 2023
Updated
Mar 26, 2025
Vendor
F5 Networks
Product
BIG-IP
Classifications
CWE-476, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 1, 2023CVE publishedPublication date reported by the CVE source.
  2. Mar 26, 2025Record 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=13.1.0 <*
  2. Affected versionversion=14.1.0 <14.1.5.3
  3. Affected versionversion=15.1.0 <15.1.8.1
  4. Affected versionversion=16.1.0 <16.1.3.3
  5. Affected versionversion=17.0.0 <17.0.0.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

F5 Networks · BIG-IPversion=13.1.0 <*; version=14.1.0 <14.1.5.3; version=15.1.0 <15.1.8.1; version=16.1.0 <16.1.3.3; version=17.0.0 <17.0.0.2

Published CVSS scores

7.5F5 NetworksCVSS: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-476NULL Pointer Dereference
T1499.004Endpoint Denial of Service: Application 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

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Your stack

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