Remote code execution via heap buffer overflow
Published Sep 8, 2026 · Updated Sep 9, 2026
Heap-based buffer overflow in Microsoft Windows 11 24H2 before build 26100.9445 allows remote attackers to execute code over a network. Microsoft has not disclosed the specific Print Spooler parsing or copy operation that overwrites the heap buffer. Exploitation requires an unauthenticated network path and user interaction; successful exploitation executes code in the affected system context.
Summary
What happened
Heap-based buffer overflow in Microsoft Windows 11 24H2 before build 26100.9445 allows remote attackers to execute code over a network. Microsoft has not disclosed the specific Print Spooler parsing or copy operation that overwrites the heap buffer. Exploitation requires an unauthenticated network path and user interaction; successful exploitation executes code in the affected system context.
The record
- CVE
- CVE-2026-85877
- Published
- Sep 8, 2026
- Updated
- Sep 9, 2026
- Vendor
- Microsoft
- Product
- Windows 11, version 24H2
- Classifications
- CWE-122, T1203
- 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=10.0.26100.0 <10.0.26100.9445
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.
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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