Code execution via escaped Janino expressions
Published Jun 24, 2026 · Updated Jun 24, 2026
Code injection in QOS.ch logback-core 0.9.20 through 1.5.36 allows local users to execute arbitrary code through conditional configuration. The condition attribute of if elements passes Janino-evaluated Java expressions after a filter fails to reject Unicode escapes encoding the prohibited new operator. Exploitation requires Janino on the class path and either configuration-file write access or control of a configuration environment variable before startup; code runs in the application context.
Summary
What happened
Code injection in QOS.ch logback-core 0.9.20 through 1.5.36 allows local users to execute arbitrary code through conditional configuration. The condition attribute of if elements passes Janino-evaluated Java expressions after a filter fails to reject Unicode escapes encoding the prohibited new operator. Exploitation requires Janino on the class path and either configuration-file write access or control of a configuration environment variable before startup; code runs in the application context.
The record
- CVE
- CVE-2026-13006
- Published
- Jun 24, 2026
- Updated
- Jun 24, 2026
- Vendor
- QOS.ch Sarl
- Product
- logback-core
- Classifications
- CWE-20, CAPEC-242
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Jun 24, 2026CVE publishedPublication date reported by the CVE source.
- Jun 24, 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=0.9.20 <=1.5.134
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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