Code execution via prefix-only session path check
Published Mar 1, 2021 · Updated Feb 13, 2025
Deserialization in Apache Tomcat allows local users to execute code by triggering the loading of a crafted persisted session file. FileStore.file() compares canonical path strings with startsWith(), so a session identifier can select a sibling path sharing the storage-directory prefix and cause Tomcat to deserialize attacker-controlled data. Exploitation requires control of the file's contents and name, a known relative path, PersistentManager with FileStore, and a null or lax class-name filter.
Summary
What happened
Deserialization in Apache Tomcat allows local users to execute code by triggering the loading of a crafted persisted session file. FileStore.file() compares canonical path strings with startsWith(), so a session identifier can select a sibling path sharing the storage-directory prefix and cause Tomcat to deserialize attacker-controlled data. Exploitation requires control of the file's contents and name, a known relative path, PersistentManager with FileStore, and a null or lax class-name filter.
The record
- CVE
- CVE-2021-25329
- Published
- Mar 1, 2021
- Updated
- Feb 13, 2025
- Vendor
- The Apache Software Foundation
- Product
- Apache Tomcat
- Classifications
- CWE-502, T1190
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 1, 2021CVE publishedPublication date reported by the CVE source.
- Feb 13, 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.
- Affected versionversion=Apache Tomcat 10 <10.0.0
- Affected versionversion=Apache Tomcat 7 <7.0.107
- Affected versionversion=Apache Tomcat 8.5 <8.5.61
- Affected versionversion=Apache Tomcat 9 <9.0.41
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
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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