Credential interception via missing hostname verification
Published Jul 24, 2026 · Updated Jul 24, 2026
Certificate validation in Java Apereo CAS Client 4.1.0 and Jasig CAS Client 3.6.4 allows man-in-the-middle attackers to intercept CAS exchanges. The client checks the requested URL against an allowlist or regular expression but accepts any CA-trusted certificate without matching its hostname to that URL. A network-positioned attacker with a certificate for another hostname can capture a victim's Ticket-Granting Ticket and obtain Service Tickets during an active CAS exchange.
Summary
What happened
Certificate validation in Java Apereo CAS Client 4.1.0 and Jasig CAS Client 3.6.4 allows man-in-the-middle attackers to intercept CAS exchanges. The client checks the requested URL against an allowlist or regular expression but accepts any CA-trusted certificate without matching its hostname to that URL. A network-positioned attacker with a certificate for another hostname can capture a victim's Ticket-Granting Ticket and obtain Service Tickets during an active CAS exchange.
The record
- CVE
- CVE-2026-15243
- Published
- Jul 24, 2026
- Updated
- Jul 24, 2026
- Vendor
- Apereo
- Product
- Apereo CAS Client for Java
- Classifications
- CWE-297, T1557
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 24, 2026CVE publishedPublication date reported by the CVE source.
- Jul 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?
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- Affected versionversion=3.6.4
- Affected versionversion=4.1.0
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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Weakness, pattern, technique
Public exploit references
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Technologies
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Your stack
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