Cross-context authentication via cached first realm
Published Sep 23, 2026 · Updated Sep 23, 2026
Improper authentication in affected Apache Tomcat 8.5, 9.0, 10.1, and 11.0 releases allows remote attackers to cross realm boundaries. AuthenticatorBase cached one JASPIC provider and callback state, causing the first web application's realm to be reused instead of resolving state per context. Exploitation requires SimpleAuthConfigProvider as the default for multiple web applications; an identity accepted by the first realm is then evaluated across the other applications.
Summary
What happened
Improper authentication in affected Apache Tomcat 8.5, 9.0, 10.1, and 11.0 releases allows remote attackers to cross realm boundaries. AuthenticatorBase cached one JASPIC provider and callback state, causing the first web application's realm to be reused instead of resolving state per context. Exploitation requires SimpleAuthConfigProvider as the default for multiple web applications; an identity accepted by the first realm is then evaluated across the other applications.
The record
- CVE
- CVE-2026-75973
- Published
- Sep 23, 2026
- Updated
- Sep 23, 2026
- Vendor
- The Apache Software Foundation
- Product
- Apache Tomcat
- Classifications
- CWE-287, T1078
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 23, 2026CVE publishedPublication date reported by the CVE source.
- Sep 23, 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=10.1.0-M1 <=10.1.59
- Affected versionversion=11.0.0-M1 <=11.0.25
- Affected versionversion=8.5.0 <=8.5.100
- Affected versionversion=9.0.0.M4 <=9.0.121
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
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.
Activity data is delayed. The latest report is Sep 28, 2026.
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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