Unauthenticated service interruption via uncontrolled recursion
Published Sep 8, 2026 · Updated Sep 9, 2026
Uncontrolled recursion in Microsoft Exchange Server allows remote attackers to interrupt the service through network requests. Microsoft has not disclosed the affected code path, request format, or recursive operation that fails to impose a termination bound. Exploitation requires no authentication or user interaction, and the documented consequence is limited to loss of service availability.
Summary
What happened
Uncontrolled recursion in Microsoft Exchange Server allows remote attackers to interrupt the service through network requests. Microsoft has not disclosed the affected code path, request format, or recursive operation that fails to impose a termination bound. Exploitation requires no authentication or user interaction, and the documented consequence is limited to loss of service availability.
The record
- CVE
- CVE-2026-69378
- Published
- Sep 8, 2026
- Updated
- Sep 9, 2026
- Vendor
- Microsoft
- Product
- Microsoft Exchange Server 2019 Cumulative Update 14
- Classifications
- CWE-674, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 8, 2026CVE publishedPublication date reported by the CVE source.
- Sep 9, 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=15.02.0.0 <15.02.1544.046
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
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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