Kernel fault via oversized DCTCP shift parameter
Published Jun 21, 2024 · Updated May 12, 2026
Out-of-bounds shifting in Linux kernel DCTCP allows local users to trigger undefined behavior through a writable module parameter. dctcp_update_alpha() uses dctcp_shift_g directly as a right-shift exponent and in the expression 10 minus dctcp_shift_g without enforcing an upper bound. The trigger requires local write access to the tcp_dctcp sysfs parameter; the observed result is a UBSAN fault during TCP acknowledgment processing.
Summary
What happened
Out-of-bounds shifting in Linux kernel DCTCP allows local users to trigger undefined behavior through a writable module parameter. dctcp_update_alpha() uses dctcp_shift_g directly as a right-shift exponent and in the expression 10 minus dctcp_shift_g without enforcing an upper bound. The trigger requires local write access to the tcp_dctcp sysfs parameter; the observed result is a UBSAN fault during TCP acknowledgment processing.
The record
- CVE
- CVE-2024-37356
- Published
- Jun 21, 2024
- Updated
- May 12, 2026
- Vendor
- Siemens
- Product
- SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
- Classifications
- CWE-125, T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 21, 2024CVE publishedPublication date reported by the CVE source.
- May 12, 2026Record updatedLatest update available in the CVE record.
Exploitability
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Is a vulnerable build present?
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- Affected versionversion=V3.1.0 <V3.1.5
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
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Your stack
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