Kernel stack-memory read via unchecked USB-PD length
Published Jul 19, 2026 · Updated Jul 19, 2026
Uninitialized-memory use in Linux Kernel allows physically proximate attackers to trigger a kernel stack-memory read with a malformed USB-PD frame. The TCPM TCPCI Maxim receive path trusts the header's NDO count without checking RX_BYTE_CNT, so parsing reads data objects absent from the received body. A malicious or broken USB Type-C port must supply a CRC-valid header and shorter body; the published record does not establish a further consequence from the uninitialized data.
Summary
What happened
Uninitialized-memory use in Linux Kernel allows physically proximate attackers to trigger a kernel stack-memory read with a malformed USB-PD frame. The TCPM TCPCI Maxim receive path trusts the header's NDO count without checking RX_BYTE_CNT, so parsing reads data objects absent from the received body. A malicious or broken USB Type-C port must supply a CRC-valid header and shorter body; the published record does not establish a further consequence from the uninitialized data.
The record
- CVE
- CVE-2026-63959
- Published
- Jul 19, 2026
- Updated
- Jul 19, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- T1200
- Attack vector
- physical
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 19, 2026CVE publishedPublication date reported by the CVE source.
- Jul 19, 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 <6.12.93
- Affected versionversion=0 <6.18.35
- Affected versionversion=0 <6.6.143
- Affected versionversion=0 <7.0.12
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <0af00f1459f5dd757f0d392f8caa38039561ac62
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9b496e3371c04f0a03b7faa5d2442536d00e3998
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <aa2f716327be1818e1cb156da8a2844804aaec2f
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c4ab8e2d4432abb646c5c0687f8dab173da901f9
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <dc17721d42e6d89f63572e63add8306a0e15eb3c
What conditions does exploitation require?
What is affected?
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.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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