CVE-2025-55669Network attack vector

Unauthenticated service interruption via undisclosed HTTP/2 traffic

Published Oct 15, 2025 · Updated Oct 15, 2025

Denial of service in F5 BIG-IP 16.1.0 through 16.1.5 and 17.1.0 through 17.1.2.1 allows remote attackers to terminate TMM. F5 has not disclosed which HTTP/2 parsing or resource-lifecycle operation mishandles the crafted traffic. Exploitation requires an Advanced WAF/ASM security policy and a server-side HTTP/2 profile on the same virtual server, and interruption is limited to traffic handled by the terminated process.

CVSS severity8.7
High
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in F5 BIG-IP 16.1.0 through 16.1.5 and 17.1.0 through 17.1.2.1 allows remote attackers to terminate TMM. F5 has not disclosed which HTTP/2 parsing or resource-lifecycle operation mishandles the crafted traffic. Exploitation requires an Advanced WAF/ASM security policy and a server-side HTTP/2 profile on the same virtual server, and interruption is limited to traffic handled by the terminated process.

The record

CVE
CVE-2025-55669
Published
Oct 15, 2025
Updated
Oct 15, 2025
Vendor
F5 Networks
Product
BIG-IP
Classifications
CWE-672, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 15, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 15, 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=16.1.0 <16.1.6
  2. Affected versionversion=17.1.0 <17.1.2.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

F5 Networks · BIG-IPversion=16.1.0 <16.1.6; version=17.1.0 <17.1.2.2

Published CVSS scores

7.5F5 NetworksCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
8.7F5 NetworksCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L

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-672Operation on a Resource after Expiration or Release
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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