CVE Catalog

CVE-2026-97953

HighCVSS 7.0
Published: Updated: Translated: NVD NIST

Summary

In the Linux kernel, the stmmac driver has an issue with TX descriptor availability for TSO traffic. The estimation of free descriptors is inaccurate, potentially leading to writing past available descriptors and corrupting the TX ring. The fix adds a function to compute the exact number of descriptors needed.

Risk Assessment

TX ring corruption can lead to network failure, packet loss, or potential remote code execution. The issue occurs with highly fragmented TSO packets.

Recommendation

Apply a Linux kernel update containing the fix for the stmmac driver. Monitor TSO traffic and limit fragmentation if possible.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: net: stmmac: fix TX descriptor availability check for TSO traffic stmmac_tso_xmit() estimates the number of free TX descriptors required by a TSO skb as: (skb->len - proto_hdr_len) / TSO_MAX_BUFF_SIZE + 1 which assumes the payload is split into TSO_MAX_BUFF_SIZE chunks. This underestimates the descriptors actually consumed by stmmac_tso_allocator(), since each fragment is mapped individually and so it needs at least one descriptor regardless of its size. Moreover, one descriptor is used for the L2/L3/L4 headers and, when the MSS changes, one more is consumed for the MSS context descriptor. For a highly fragmented TSO skb the check can therefore pass even when the ring has too few free slots. stmmac_tso_allocator() then writes past the available descriptors, overwriting descriptors still owned by the DMA engine, corrupting the TX ring. Add stmmac_tso_get_num_desc() to compute the exact number of descriptors needed for the header, the linear payload and each fragment, plus the MSS context descriptor when required, and use it in the availability check.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS