Kernel disclosure or crash via short compound request
Published Aug 5, 2026 · Updated Aug 5, 2026
Out-of-bounds read in Linux ksmbd allows remote attackers to disclose adjacent kernel memory or crash the host via crafted SMB2 traffic. ksmbd_smb2_check_message() reads the two-byte StructureSize2 field at offset 64 before confirming that a trailing compound element extends beyond its 64-byte SMB2 header. No authentication or user interaction is required when ksmbd listens on TCP port 445; the read reaches one byte beyond the buffer, and repeated requests can panic the kernel.
Summary
What happened
Out-of-bounds read in Linux ksmbd allows remote attackers to disclose adjacent kernel memory or crash the host via crafted SMB2 traffic. ksmbd_smb2_check_message() reads the two-byte StructureSize2 field at offset 64 before confirming that a trailing compound element extends beyond its 64-byte SMB2 header. No authentication or user interaction is required when ksmbd listens on TCP port 445; the read reaches one byte beyond the buffer, and repeated requests can panic the kernel.
The record
- CVE
- CVE-2026-64578
- Published
- Aug 5, 2026
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 5, 2026CVE publishedPublication date reported by the CVE source.
- Aug 5, 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=5.15
- Affected versionversion=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <15b38176fd1530372905c602fde51fe89ec8c877
- Affected versionversion=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <2c307126ed8e7adddab82b8e31d962d3a2156ab1
- Affected versionversion=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <ea128f06d2fb2186f0cac0c9f3e953e4d1f5c29a
- Affected versionversion=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <f0e337e7db67cc1c832958bbb6c4026bdceacfdb
- Affected versionversion=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <f7550a91ab211726f59cb137523b7a9eae1ac6eb
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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