{"id":"CVE-2026-97953","published":"2026-09-25T11:17:22.930","lastModified":"2026-09-25T15:18:02.970","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: stmmac: fix TX descriptor availability check for TSO traffic\n\nstmmac_tso_xmit() estimates the number of free TX descriptors required by\na TSO skb as:\n\n\t(skb->len - proto_hdr_len) / TSO_MAX_BUFF_SIZE + 1\n\nwhich assumes the payload is split into TSO_MAX_BUFF_SIZE chunks. This\nunderestimates the descriptors actually consumed by stmmac_tso_allocator(),\nsince each fragment is mapped individually and so it needs at least one\ndescriptor regardless of its size. Moreover, one descriptor is used for\nthe L2/L3/L4 headers and, when the MSS changes, one more is consumed for\nthe MSS context descriptor.\nFor a highly fragmented TSO skb the check can therefore pass even when the\nring has too few free slots. stmmac_tso_allocator() then writes past the\navailable descriptors, overwriting descriptors still owned by the DMA\nengine, corrupting the TX ring.\nAdd stmmac_tso_get_num_desc() to compute the exact number of descriptors\nneeded for the header, the linear payload and each fragment, plus the MSS\ncontext descriptor when required, and use it in the availability check.","cvssScore":7,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H","cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/5e38d732ec67a5b1f9a56e6c73add480c4b6030a","tags":[]},{"url":"https://git.kernel.org/stable/c/65820fc743eae322f7f94f6a64d07861211d4b21","tags":[]},{"url":"https://git.kernel.org/stable/c/c28175220f808c867d5618de8ecc6dbcc815c773","tags":[]},{"url":"https://git.kernel.org/stable/c/ffa6d2481bc1c87f822ecd626561484e4ee24cef","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}