Authenticated heap-memory disclosure via sparse stream writes
Published Oct 15, 2025 · Updated Oct 15, 2025
Information disclosure in Samba's vfs_streams_xattr module allows remote authenticated users to read residual heap data over SMB. streams_xattr_pwrite() creates holes in alternate data streams without initializing the backing heap memory, exposing repeated samples of discarded contents. Exposure requires an authenticated account and the streams_xattr VFS module; the result is residual-memory disclosure without data modification or service interruption.
Summary
What happened
Information disclosure in Samba's vfs_streams_xattr module allows remote authenticated users to read residual heap data over SMB. streams_xattr_pwrite() creates holes in alternate data streams without initializing the backing heap memory, exposing repeated samples of discarded contents. Exposure requires an authenticated account and the streams_xattr VFS module; the result is residual-memory disclosure without data modification or service interruption.
The record
- CVE
- CVE-2025-9640
- Published
- Oct 15, 2025
- Updated
- Oct 15, 2025
- Vendor
- 389 Directory Server
- Product
- Red Hat Enterprise Linux 6
- Classifications
- CWE-908, T1190
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Oct 15, 2025CVE publishedPublication date reported by the CVE source.
- Oct 15, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
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
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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