Local file overwrite via symlink-following output open
Published Jul 15, 2026 · Updated Jul 15, 2026
Symlink following in Microsoft AVML before 0.17.0 allows local users to truncate or overwrite files via a crafted Unix output path. The open_dst path handler creates and truncates the destination with O_TRUNC before fully validating input, without blocking symbolic links. Exploitation requires control of the destination path or its directory, and the target is modified with the privileges of the AVML process.
Summary
What happened
Symlink following in Microsoft AVML before 0.17.0 allows local users to truncate or overwrite files via a crafted Unix output path. The open_dst path handler creates and truncates the destination with O_TRUNC before fully validating input, without blocking symbolic links. Exploitation requires control of the destination path or its directory, and the target is modified with the privileges of the AVML process.
The record
- CVE
- CVE-2026-61371
- Published
- Jul 15, 2026
- Updated
- Jul 15, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-59, T1565.001
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 15, 2026CVE publishedPublication date reported by the CVE source.
- Jul 15, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
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.
Weakness, pattern, technique
Public exploit references
- AVML symlink overwrite and truncation proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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