Bug 2524473 (CVE-2026-74737)

Summary: CVE-2026-74737 kernel: net: ethernet: ti: am65-cpsw-nuss: Fix port_id extraction from SRC TAG
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's `am65-cpsw-nuss` Ethernet driver. When processing incoming network packets, the driver incorrectly extracts the MAC Port ID from the Source Tag, using 16 bits instead of the intended lower 8 bits. This error can lead to the driver accessing out-of-bound memory, resulting in a sporadic kernel crash. A remote attacker could potentially exploit this vulnerability by sending specially crafted network packets, leading to a Denial of Service (DoS) condition.
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Description OSIDB Bzimport 2026-08-26 14:58:02 UTC 
In the Linux kernel, the following vulnerability has been resolved:

net: ethernet: ti: am65-cpsw-nuss: Fix port_id extraction from SRC TAG

On the packet reception path, the ID of the MAC Port on which the packet
was received, is embedded in the RX DMA Descriptor's metadata. The ID is
extracted using the helper function cppi5_desc_get_tags_ids() which fills
in the 16-bit Source Tag into the 'port_id' variable. However, it is only
the lower 8-bits of the 16-bit Source Tag that represent the MAC Port ID,
while the upper 8-bits are Hardware-Reserved and carry an arbitrary value.
With the existing logic, sporadic kernel crash is observed due to the
subsequent driver code accessing out-of-bound memory because of an invalid
port_id.

Hence, fix the port_id extraction logic to use only the lower 8-bits of the
Source Tag as the MAC Port ID.
Comment 1 gkamathe 2026-08-27 10:41:40 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026082656-CVE-2026-74737-bf95@gregkh/T