Medium [CVE-2026-74409] add bounds check on firmware mac_id in link lookup
This medium-severity Red Hat Linux advisory covers CVE-2026-74409 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat package: kernel-rt.
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Summary
In the Linux kernel, the following vulnerability has been resolved: wifi: rtw89: add bounds check on firmware mac_id in link lookup The mac_id field in RX descriptors is 8 bits wide (0-255), but assoc_link_on_macid[] has only RTW89_MAX_MAC_ID_NUM (128) entries.
While the driver currently assigns mac_id values below 128, the descriptor value comes from firmware and is not validated before use as an array index. Add a defensive bounds check in rtw89_assoc_link_rcu_dereference() to guard against out-of-range firmware values.
A flaw was found in the Realtek rtw89 Wi-Fi driver in the Linux kernel. This vulnerability arises from insufficient validation of the `mac_id` field, which is received from firmware and used as an array index.
An attacker could potentially craft malicious firmware to provide an out-of-range `mac_id`, leading to an out-of-bounds read. This could result in memory corruption or a denial of service.
Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-125.
Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 9. Red Hat does not currently list a fixing RHSA for this CVE.
Affected products named by the advisory: Red Hat package: kernel-rt.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 2 hours ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 2 hours ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 2 hours ago·verify at source
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