Bug 2536143 (CVE-2026-90398)

Summary: CVE-2026-90398 kernel: wifi: ath11k: fix stride mismatch in mac_phy_caps_parse()
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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Doc Text:
A flaw was found in the Linux kernel ath11k Wi-Fi driver. This vulnerability occurs in the mac_phy_caps_parse() function due to a mismatch between the allocated memory size and the size used for copying data. When processing certain firmware messages, the driver attempts to write information beyond the intended memory boundary. This out-of-bounds write can lead to memory corruption within the kernel.
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Description OSIDB Bzimport 2026-09-17 16:40:23 UTC 
In the Linux kernel, the following vulnerability has been resolved:

wifi: ath11k: fix stride mismatch in mac_phy_caps_parse()

Currently, in ath11k_wmi_tlv_mac_phy_caps_parse(), kcalloc() sizes the
mac_phy_caps buffer as tot_phy_id * len, where len is clamped to
min(firmware_len, sizeof(struct wmi_mac_phy_capabilities)). The subsequent
memcpy() destination advances by sizeof(full struct) per slot via C
pointer arithmetic, not by the clamped len. When firmware sends short
TLVs, the second and later slots are written past the end of the
allocation.

The reader in ath11k_pull_mac_phy_cap_svc_ready_ext() also indexes the
buffer with full-struct pointer arithmetic, so the allocation must match
that stride.

Fix by using kzalloc_objs(), which derives the element size from the
pointer type, making allocation size and pointer stride provably
consistent regardless of what len the firmware provides.

Compile tested only.
Comment 1 gkamathe 2026-09-21 09:44:28 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90398.mbox