Theoretical EOP ring misconfiguration via size underflow
Published Oct 6, 2026 · Updated Oct 6, 2026
Integer underflow in Linux before 7.2.8 can misencode the AMD KFD EOP ring size when a queue buffer is smaller than 4096 bytes. The update_mqd and __update_mqd paths subtract one from the base-2 logarithm of a quarter-sized buffer before setting cp_hqd_eop_control; a zero logarithm would underflow. The upstream patch states that ring buffers cannot be smaller than 4096 bytes in practice, so the triggering condition and any attacker impact remain unproven.
Summary
What happened
Integer underflow in Linux before 7.2.8 can misencode the AMD KFD EOP ring size when a queue buffer is smaller than 4096 bytes. The update_mqd and __update_mqd paths subtract one from the base-2 logarithm of a quarter-sized buffer before setting cp_hqd_eop_control; a zero logarithm would underflow. The upstream patch states that ring buffers cannot be smaller than 4096 bytes in practice, so the triggering condition and any attacker impact remain unproven.
The record
- CVE
- CVE-2026-98177
- Published
- Oct 6, 2026
- Updated
- Oct 6, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- Unavailable
- Attack vector
- Unavailable
- Privileges
- Unavailable
Timeline
How it unfolded
- Oct 6, 2026CVE publishedPublication date reported by the CVE source.
- Oct 6, 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 <7.2.8
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <287a34c4d712e0bdb67751e21316d9c8d75a528a
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8ee521b8b189799e361d4233c5180ba56656d4d4
What conditions does exploitation require?
What is affected?
Published CVSS scores
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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
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Public exploit references
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Technologies
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