Kernel data disclosure via stale ciphertext length
Published Aug 19, 2025 · Updated Aug 5, 2026
Information disclosure in Linux from commit 7246d8ed4dcc allows remote attackers to receive uninitialized kernel data in TLS records. The kTLS software transmit path keeps the original ciphertext length after a BPF socket policy uses bpf_msg_pop_data() to shorten plaintext, so tls_sw.c sends bytes beyond the recalculated record. Exploitation requires kTLS traffic through that socket-policy helper; the peer receives kernel-buffer residue followed by a TLS parsing error.
Summary
What happened
Information disclosure in Linux from commit 7246d8ed4dcc allows remote attackers to receive uninitialized kernel data in TLS records. The kTLS software transmit path keeps the original ciphertext length after a BPF socket policy uses bpf_msg_pop_data() to shorten plaintext, so tls_sw.c sends bytes beyond the recalculated record. Exploitation requires kTLS traffic through that socket-policy helper; the peer receives kernel-buffer residue followed by a TLS parsing error.
The record
- CVE
- CVE-2025-38608
- Published
- Aug 19, 2025
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- Unavailable
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 19, 2025CVE 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=5.0
- Affected versionversion=7246d8ed4dcce23f7509949a77be15fa9f0e3d28 <0e853c1464bcf61207f8b5c32d2ac5ee495e859d
- Affected versionversion=7246d8ed4dcce23f7509949a77be15fa9f0e3d28 <16aca8bb4ad0d8a13c8b6da4007f4e52d53035bb
- Affected versionversion=7246d8ed4dcce23f7509949a77be15fa9f0e3d28 <178f6a5c8cb3b6be1602de0964cd440243f493c9
- Affected versionversion=7246d8ed4dcce23f7509949a77be15fa9f0e3d28 <1e480387d4b42776f8957fb148af9d75ce93b96d
- Affected versionversion=7246d8ed4dcce23f7509949a77be15fa9f0e3d28 <6ba20ff3cdb96a908b9dc93cf247d0b087672e7c
- Affected versionversion=7246d8ed4dcce23f7509949a77be15fa9f0e3d28 <73fc5d04009d3969ff8e8574f0fd769f04124e59
- Affected versionversion=7246d8ed4dcce23f7509949a77be15fa9f0e3d28 <849d24dc5aed45ebeb3490df429356739256ac40
- Affected versionversion=7246d8ed4dcce23f7509949a77be15fa9f0e3d28 <90d6ef67440cec2a0aad71a0108c8f216437345c
- Affected versionversion=7246d8ed4dcce23f7509949a77be15fa9f0e3d28 <ee03766d79de0f61ea29ffb6ab1c7b196ea1b02e
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
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Public exploit references
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Technologies
Your stack
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Your stack
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