CVE-2026-25518Network attack vector

Controller crash via miscast cached DNS answer

Published Feb 4, 2026 · Updated Feb 4, 2026

Denial of service in cert-manager 1.18.0 through 1.18.4 and 1.19.0 through 1.19.2 allows remote attackers to crash the controller using crafted DNS data. FindZoneByFqdn assumes the first answer in a cached DNS response is an SOA record and performs an unchecked type assertion on that entry. Exploitation requires interception and modification of the controller pod's DNS traffic or control of the authoritative DNS server for a domain undergoing ACME DNS-01 validation.

CVSS severity5.9
Medium
EPSS probability0.36%
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 cert-manager 1.18.0 through 1.18.4 and 1.19.0 through 1.19.2 allows remote attackers to crash the controller using crafted DNS data. FindZoneByFqdn assumes the first answer in a cached DNS response is an SOA record and performs an unchecked type assertion on that entry. Exploitation requires interception and modification of the controller pod's DNS traffic or control of the authoritative DNS server for a domain undergoing ACME DNS-01 validation.

The record

CVE
CVE-2026-25518
Published
Feb 4, 2026
Updated
Feb 4, 2026
Vendor
cert-manager
Product
cert-manager
Classifications
CWE-704, CWE-129, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 4, 2026Record 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=>= 1.18.0, < 1.18.5
  2. Affected versionversion=>= 1.19.0, < 1.19.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

cert-manager · cert-managerversion=>= 1.18.0, < 1.18.5; version=>= 1.19.0, < 1.19.3

Published CVSS scores

5.9GitHub, Inc.CVSS:3.1/AV:N/AC:H/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-704Incorrect Type Conversion or Cast
CWE-129Improper Validation of Array Index
T1499.004Application 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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