Bug 2514463 (CVE-2026-68449)

Summary: CVE-2026-68449 kernel: ata: sata_dwc_460ex: fix infinite loop in NCQ tag completion bit-scanning
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's `sata_dwc_460ex` component. A hand-rolled bit-scanning loop in the NCQ tag completion path contains an infinite loop bug. When a specific `tag_mask` value is processed, the loop can overflow, causing an infinite loop in a hard interrupt request (hardirq) context while a spinlock is held. This can lead to a system hang or crash, resulting in a Denial of Service (DoS).
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-08-12 01:11:15 UTC 
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.
Comment 1 gkamathe 2026-08-12 04:57:02 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081225-CVE-2026-68449-a314@gregkh/T