CVE-2025-59781Network attack vector

Memory exhaustion via incomplete DNS cache cleanup

Published Oct 15, 2025 · Updated Oct 15, 2025

Incomplete cleanup in F5 BIG-IP and BIG-IP Next CNF allows remote attackers to exhaust memory through crafted DNS queries. The DNS cache fails to release resources after processing undisclosed query forms, causing memory use to grow; F5 has not identified the affected code path. The issue is reachable only when DNS cache is configured on a virtual server, and the documented consequence is service interruption without data disclosure or modification.

CVSS severity8.7
High
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incomplete cleanup in F5 BIG-IP and BIG-IP Next CNF allows remote attackers to exhaust memory through crafted DNS queries. The DNS cache fails to release resources after processing undisclosed query forms, causing memory use to grow; F5 has not identified the affected code path. The issue is reachable only when DNS cache is configured on a virtual server, and the documented consequence is service interruption without data disclosure or modification.

The record

CVE
CVE-2025-59781
Published
Oct 15, 2025
Updated
Oct 15, 2025
Vendor
F5 Networks
Product
BIG-IP
Classifications
CWE-459, 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=15.1.0 <15.1.10.8
  2. Affected versionversion=16.1.0 <16.1.6
  3. 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=15.1.0 <15.1.10.8; version=16.1.0 <16.1.6; version=17.1.0 <17.1.2.2
F5 Networks · BIG-IP Next CNFversion=1.1.0 <* changes=[{"at":"1.4.0-EHF-3","status":"unaffected"}]

Published CVSS scores

7.5F5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
8.7F5CVSS: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-459Incomplete Cleanup
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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