SB20261022417 - Use of uninitialized resource in Linux kernel stmicro stmmac driver

Description

This security bulletin contains information about 1 vulnerability.

1) Use of uninitialized resource (CVE-ID: CVE-2026-98803)

CWE-ID: CWE-908 - Use of Uninitialized Resource

CVSSv4: 5.3 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker on the local network to cause a denial of service in network receive processing.

The vulnerability exists due to use of an uninitialized secondary DMA buffer in the stmmac receive path when processing frames larger than dma_buf_sz without split-header mode. A remote attacker on the local network can send a frame that overflows the primary receive buffer to trigger a DMA write to an unmapped secondary-buffer address and an SMMU translation fault on IOMMU-based platforms.

AF_XDP zero-copy receive queues also expose this fault condition because their secondary buffer is programmed with DMA address 0.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/358d5ac5a5d57ce21c3814c4e3e8f3fbcb7304b4
• https://git.kernel.org/stable/c/88095728511e0df9c89528944f5a1762ad298983
• https://git.kernel.org/stable/c/a7cff44543f66f3a19151060cb549691d191d44c