Kernel out-of-bounds read via oversized SMB1 filename
Published Sep 24, 2026 · Updated Sep 24, 2026
Out-of-bounds read in the Linux CIFS client allows remote attackers to trigger a read past a response buffer through a malformed SMB1 directory entry. cifs_filldir trusts the server-supplied FileNameLength and passes the unchecked span to memchr, which reads beyond the SMB response slab buffer. A local user must list a CIFS directory mounted from an attacker-controlled server; published evidence establishes the invalid read and KASAN report, not data disclosure, code execution, or a production-kernel crash.
Summary
What happened
Out-of-bounds read in the Linux CIFS client allows remote attackers to trigger a read past a response buffer through a malformed SMB1 directory entry. cifs_filldir trusts the server-supplied FileNameLength and passes the unchecked span to memchr, which reads beyond the SMB response slab buffer. A local user must list a CIFS directory mounted from an attacker-controlled server; published evidence establishes the invalid read and KASAN report, not data disclosure, code execution, or a production-kernel crash.
The record
- CVE
- CVE-2026-93787
- Published
- Sep 24, 2026
- Updated
- Sep 24, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- Unavailable
- Attack vector
- network
- Privileges
- Unavailable
Timeline
How it unfolded
- Sep 24, 2026CVE publishedPublication date reported by the CVE source.
- Sep 24, 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=0 <6.12.111
- Affected versionversion=0 <6.18.53
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <03003506c86f90312b0966283662c42fcab66e4b
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <6e3b965267b7313903baba2739992b1e2e92d540
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f8cf09a53a0dc1da298e9dd0ba5f21710cf119d6
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
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.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
No sourced classifications are available.
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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