Local kernel crash via empty TLS record
Published May 21, 2024 · Updated May 11, 2026
NULL pointer dereference in Linux kernel 6.5 allows local users to crash the system through sendfile() on an empty TLS record. The tls_sw_splice_eof() path passes empty plaintext and ciphertext sk_msg buffers into tls_push_record(), selects a split path, and reaches tls_merge_open_record(), which dereferences a nonexistent buffer element. Exploitation requires local low-privileged access and the empty TLS buffer state left by tls_trim_both_msgs(); the bounded consequence is a kernel crash.
Summary
What happened
NULL pointer dereference in Linux kernel 6.5 allows local users to crash the system through sendfile() on an empty TLS record. The tls_sw_splice_eof() path passes empty plaintext and ciphertext sk_msg buffers into tls_push_record(), selects a split path, and reaches tls_merge_open_record(), which dereferences a nonexistent buffer element. Exploitation requires local low-privileged access and the empty TLS buffer state left by tls_trim_both_msgs(); the bounded consequence is a kernel crash.
The record
- CVE
- CVE-2023-52767
- Published
- May 21, 2024
- Updated
- May 11, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-476, T1499
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- May 21, 2024CVE publishedPublication date reported by the CVE source.
- May 11, 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?
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- Affected versionversion=5ad627faed136089e27bcd15e0c33760e575c8c3 <944900fe2736c07288efe2d9394db4d3ca23f2c9
- Affected versionversion=6.5
- Affected versionversion=df720d288dbb1793e82b6ccbfc670ec871e9def4 <2214e2bb5489145aba944874d0ee1652a0a63dc8
- Affected versionversion=df720d288dbb1793e82b6ccbfc670ec871e9def4 <53f2cb491b500897a619ff6abd72f565933760f0
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Public exploit references
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Technologies
Your stack
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Your stack
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