Local code execution via ReFS heap overflow
Published Jul 14, 2026 · Updated Jul 14, 2026
Heap-based buffer overflow in Microsoft Windows ReFS allows local users with low privileges to execute code through local system access. Microsoft identifies ReFS and heap memory corruption but has not published the triggering input, parsing routine, or faulty memory operation. Exploitation requires local access and low privileges, needs no user interaction, and yields code execution in the affected ReFS context.
Summary
What happened
Heap-based buffer overflow in Microsoft Windows ReFS allows local users with low privileges to execute code through local system access. Microsoft identifies ReFS and heap memory corruption but has not published the triggering input, parsing routine, or faulty memory operation. Exploitation requires local access and low privileges, needs no user interaction, and yields code execution in the affected ReFS context.
The record
- CVE
- CVE-2026-49793
- Published
- Jul 14, 2026
- Updated
- Jul 14, 2026
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-122, T1203
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 14, 2026CVE publishedPublication date reported by the CVE source.
- Jul 14, 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 <10.0.17763.9020
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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