Remote code execution via double-free memory corruption
Published Sep 8, 2026 · Updated Sep 9, 2026
A double-free flaw in Microsoft Office Word on affected Windows releases allows remote attackers to execute code through network-delivered content. Microsoft identifies the defect only as a double free in Word and has not disclosed the affected parser, object-lifetime error, or triggering content structure. Exploitation requires user interaction with attacker-controlled content, after which code executes with that user's privileges.
Summary
What happened
A double-free flaw in Microsoft Office Word on affected Windows releases allows remote attackers to execute code through network-delivered content. Microsoft identifies the defect only as a double free in Word and has not disclosed the affected parser, object-lifetime error, or triggering content structure. Exploitation requires user interaction with attacker-controlled content, after which code executes with that user's privileges.
The record
- CVE
- CVE-2026-77504
- Published
- Sep 8, 2026
- Updated
- Sep 9, 2026
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-415, T1204
- 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
Compare your product and version with the public record. A matching version still requires validation against your environment.
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.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo