Linux Kernel ATA Driver Infinite Loop in NCQ Completion
CVE-2026-68449 Published on August 12, 2026
ata: sata_dwc_460ex: fix infinite loop in NCQ tag completion bit-scanning
In the Linux kernel, the following vulnerability has been resolved:
ata: sata_dwc_460ex: fix infinite loop in NCQ tag completion bit-scanning
The hand-rolled bit-scanning loop in the NCQ completion path has an
infinite loop bug. When tag_mask has only high bits set (e.g.
0x80000000), the inner while loop left-shifts tag_mask until it
overflows to 0. At that point !(0 & 1) is always true and 0 <<= 1
stays 0, causing an infinite loop in hardirq context with a spinlock
held.
Replace the open-coded bit-scanning with __ffs() which correctly
finds the least significant set bit and is bounded by the width of
the argument.
Products Associated with CVE-2026-68449
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Affected Versions
Linux:- Version 62936009f35a6659cc3ebe0d90c754182d60da73 and below 4c6e64cae2b2dab32ad9099faa339f6a72c0ce16 is affected.
- Version 62936009f35a6659cc3ebe0d90c754182d60da73 and below 8c5de0d8ab6824cfdadcbbe1be4c6c9d9f4c1f80 is affected.
- Version 62936009f35a6659cc3ebe0d90c754182d60da73 and below 1842d45f461a78988254631893329bdf4596e954 is affected.
- Version 62936009f35a6659cc3ebe0d90c754182d60da73 and below 29b916d3556bd12a95be7c56ca391b8cd572f8be is affected.
- Version 62936009f35a6659cc3ebe0d90c754182d60da73 and below c2130f6553f4a5cbdc259de069600117a995f197 is affected.
- Version 2.6.36 is affected.
- Before 2.6.36 is unaffected.
- Version 6.6.148, <= 6.6.* is unaffected.
- Version 6.12.101, <= 6.12.* is unaffected.
- Version 6.18.42, <= 6.18.* is unaffected.
- Version 7.1.6, <= 7.1.* is unaffected.
- Version 7.2-rc4, <= * is unaffected.