CVE-2025-66418VulnerabilityPublished 26 Jan 2026Updated 8 Oct 2026

Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.18.1

Affects Red HatSource GCVE Database

Not known to be exploited.

Data as of 26 Oct 2026, 08:30 UTC

Severity

High

Rated by Threat Radar · No CVSS score from NVD or the CNA

EPSS: 0.6% chance of exploitation in 30 days – higher than 52% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation evidence

Disclosed: evidence found.
CVE published 26 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Red Hat Product Security Red Hat	Affected >=1.18.0 <=1.18.1 Red Hat cert-manager operator for Red Hat OpenShift cert-manager operator for Red Hat OpenShift 1.18 amd64 registry.redhat.io/cert-manager/cert-manager-operator-rhel9@sha256:57a1aea49d7cc275b37b8f52d602a3a9d1601ec6a21a3268dd4903566cb2e335_amd64	Fixed in–

AI-suggested

The vendor advisory states that if the cert-manager Operator's installation uses the default 'Automatic' approval policy, the operator will upgrade automatically to a fixed version when available, requiring no user action. For installations with a 'Manual' approval policy, administrators must manually approve the upgrade. Before upgrading, ensure all previously released errata relevant to the system are applied. Users should monitor the Red Hat advisory RHSA-2026:1176 and related documentation for updates on patch availability and upgrade instructions. No explicit patch version is currently provided, so checking the vendor advisory regularly is recommended.

Description

The cert-manager Operator for Red Hat OpenShift builds on top of Kubernetes, introducing certificate authorities and certificates as first-class resource types in the Kubernetes API. This makes it possible to provide certificates-as-a-service to developers working within your Kubernetes cluster.

Impact

Exploitation of this vulnerability leads to denial of service conditions by exhausting CPU and memory resources on the client system running the cert-manager Operator. This can cause the operator and potentially dependent services to become unresponsive, disrupting certificate management within the Kubernetes cluster. There is no indication of confidentiality or integrity impact. No known exploits in the wild have been reported.

Summary

The cert-manager Operator for Red Hat OpenShift (versions >=1.18.0 <=1.18.1) includes a vulnerability identified as CVE-2025-66418, stemming from the urllib3 Python library. This vulnerability allows a remote attacker to trigger a denial of service by exploiting an unbounded decompression chain in HTTP responses, causing excessive CPU and memory consumption. The vulnerability is categorized under CWE-770 (Allocation of Resources Without Limits or Throttling) and CWE-409 (Improper Resource Shutdown or Release). The Red Hat advisory RHSA-2026:1176 references this and related CVEs but does not explicitly state a fixed version or patch availability. The operator's upgrade mechanism depends on the installation's approval policy; automatic upgrades occur if set, otherwise manual intervention is needed. The advisory recommends ensuring all prior errata are applied before upgrading.

CWE-770Allocation of Resources Without Limits or Throttling (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #25
The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
Requirements
Clearly specify the minimum and maximum expectations for capabilities, and dictate which behaviors are acceptable when resource allocation reaches limits.
Architecture and Design
Limit the amount of resources that are accessible to unprivileged users. Set per-user limits for resources. Allow the system administrator to define these limits. Be careful to avoid CWE-410.
Architecture and Design
Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended.
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
OWASP ASVS 4.0.3
V8.1.4 (opens in a new tab)
V13.4.1 (opens in a new tab)
V11.1.4 (opens in a new tab)
Attack patterns
XML Ping of the Death (opens in a new tab)
Exponential Data Expansion (opens in a new tab)
Serialized Data Parameter Blowup (opens in a new tab)
Serialized Data with Nested Payloads (opens in a new tab)
Oversized Serialized Data Payloads (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-409Improper Handling of Highly Compressed Data (Data Amplification) (opens in a new tab)
Base weakness
The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output.
OWASP Cheat Sheets
File Upload (opens in a new tab)
OWASP ASVS 4.0.3
V12.1.2 (opens in a new tab)
V12.1.1 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 10 Aug 2026, 17:58 UTC

WeaknessesCWE-770, CWE-409

Technical details

References

Community reviews

Related threats