Unauthenticated code execution via XDR use-after-free
Published Sep 8, 2026 · Updated Sep 9, 2026
A use-after-free in Microsoft Windows Server Services for NFS allows remote attackers to execute code through ONCRPC XDR traffic. The ONCRPC XDR driver accesses freed memory while processing untrusted network data; Microsoft has not disclosed the affected routine or object lifetime error. Reachability requires Services for NFS to be installed and exposed, and successful exploitation runs attacker-controlled code on the server.
Summary
What happened
A use-after-free in Microsoft Windows Server Services for NFS allows remote attackers to execute code through ONCRPC XDR traffic. The ONCRPC XDR driver accesses freed memory while processing untrusted network data; Microsoft has not disclosed the affected routine or object lifetime error. Reachability requires Services for NFS to be installed and exposed, and successful exploitation runs attacker-controlled code on the server.
The record
- CVE
- CVE-2026-78445
- Published
- Sep 8, 2026
- Updated
- Sep 9, 2026
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-416, T1210
- 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=10.0.17763.0 <10.0.17763.9245
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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