Controller crashes via exponential context-variable amplification
Published Jan 27, 2026 · Updated Jan 27, 2026
Unbounded memory consumption in Kyverno before 1.15.3 and 1.16.0 through 1.16.2 allows remote authenticated users to crash controllers. The policy engine evaluates chained context variables without a cumulative size limit, so repeated JMESPath join() operations exponentially expand attacker-controlled strings. Policy or ClusterPolicy creation privileges are required; successful exploitation OOM-kills admission and reports controllers, interrupting enforcement cluster-wide.
Summary
What happened
Unbounded memory consumption in Kyverno before 1.15.3 and 1.16.0 through 1.16.2 allows remote authenticated users to crash controllers. The policy engine evaluates chained context variables without a cumulative size limit, so repeated JMESPath join() operations exponentially expand attacker-controlled strings. Policy or ClusterPolicy creation privileges are required; successful exploitation OOM-kills admission and reports controllers, interrupting enforcement cluster-wide.
The record
- CVE
- CVE-2026-23881
- Published
- Jan 27, 2026
- Updated
- Jan 27, 2026
- Vendor
- Kyverno
- Product
- Kyverno
- Classifications
- CWE-770, T1562.001, T1499.003
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jan 27, 2026CVE publishedPublication date reported by the CVE source.
- Jan 27, 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.
- Affected versionversion=< 1.15.3
- Affected versionversion=>= 1.16.0, < 1.16.3
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
- Context-variable amplification proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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