Bug 2536572 (CVE-2026-90369)

Summary: CVE-2026-90369 kernel: wifi: mt76: fix out-of-bounds access in mmio copy helpers
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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 `mt76` Wi-Fi driver. The `mt76_mmio_write_copy()` and `mt76_mmio_read_copy()` functions, which handle memory-mapped I/O (MMIO) operations, can perform out-of-bounds reads or writes. This occurs when the data length is not a multiple of four, leading to memory access beyond the intended buffer. This vulnerability could result in information disclosure or a denial of service.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-09-17 18:28:35 UTC 
In the Linux kernel, the following vulnerability has been resolved:

wifi: mt76: fix out-of-bounds access in mmio copy helpers

mt76_mmio_write_copy() and mt76_mmio_read_copy() iterate up to
ALIGN(len, 4), so a length that is not a multiple of four reads past the
source buffer (write_copy) or writes past the destination (read_copy).
Copy the aligned body in the loop and handle the remaining tail through a
4-byte bounce buffer, keeping the register access width unchanged.
Comment 1 gkamathe 2026-09-22 08:29:54 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90369.mbox