Unauthenticated code execution via heap buffer overflow
Published May 12, 2026 · Updated May 12, 2026
Heap-based buffer overflow in Windows Message Queuing allows remote attackers to execute code on affected Windows systems over an adjacent network. Microsoft has not disclosed the MSMQ parsing locus, crafted input format, or bounds error that overwrites heap memory. Exploitation requires no authentication or user interaction, but the attacker must reach the MSMQ service from an adjacent network.
Summary
What happened
Heap-based buffer overflow in Windows Message Queuing allows remote attackers to execute code on affected Windows systems over an adjacent network. Microsoft has not disclosed the MSMQ parsing locus, crafted input format, or bounds error that overwrites heap memory. Exploitation requires no authentication or user interaction, but the attacker must reach the MSMQ service from an adjacent network.
The record
- CVE
- CVE-2026-34329
- Published
- May 12, 2026
- Updated
- May 12, 2026
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-122, T1210
- Attack vector
- adjacent
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 12, 2026CVE publishedPublication date reported by the CVE source.
- May 12, 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=10.0.17763.0 <10.0.17763.8755
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.
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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