{"id":"CVE-2026-99078","title":"net/mlx5e: Prevent stale XSK buffer release on MPWQE refill retry","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/mlx5e: Prevent stale XSK buffer release on MPWQE refill retry\n\nWith AF_XDP on a striding RQ, mlx5e defers releasing XSK buffers until\nan MPWQE is refilled. If XSK a…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 4c2a1323680709078736a2886c754004e9fe42e6 < f3a52e2ec2788a7f6b64137985c087188a54ad4f","Linux >= 4c2a1323680709078736a2886c754004e9fe42e6 < d215d09606b0fcd18ad1eb532995782a21cea49d","Linux >= 4c2a1323680709078736a2886c754004e9fe42e6 < 867119b4b588037724b85839d534465f0334d9bd","Linux >= 4c2a1323680709078736a2886c754004e9fe42e6 < 3d73a1164a8c6b4461907a65cb6c022ea4fd39af","Linux >= 4c2a1323680709078736a2886c754004e9fe42e6 < 63811edf512584c946e5e96b100e9e280703bbb5","Linux 6.4"],"published":"2026-10-23","updated":"2026-10-23","sourceUpdated":"2026-10-23T12:23:25.542Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-99078","references":[{"url":"https://git.kernel.org/stable/c/f3a52e2ec2788a7f6b64137985c087188a54ad4f"},{"url":"https://git.kernel.org/stable/c/d215d09606b0fcd18ad1eb532995782a21cea49d"},{"url":"https://git.kernel.org/stable/c/867119b4b588037724b85839d534465f0334d9bd"},{"url":"https://git.kernel.org/stable/c/3d73a1164a8c6b4461907a65cb6c022ea4fd39af"},{"url":"https://git.kernel.org/stable/c/63811edf512584c946e5e96b100e9e280703bbb5"}],"tags":["cve.org"],"ingestedAt":"2026-10-23T13:24:55.512Z","slug":"CVE-2026-99078","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet/mlx5e: Prevent stale XSK buffer release on MPWQE refill retry\n\nWith AF_XDP on a striding RQ, mlx5e defers releasing XSK buffers until\nan MPWQE is refilled. If XSK allocation then returns -ENOMEM,\nactual_wq_head is not advanced and a later NAPI poll retries the same\nWQE.\n\nmlx5e_free_rx_mpwqe() leaves each released slot marked as releasable. On\nretry it can therefore call xsk_buff_free() again through stale pointers\nafter the frames have returned to the XSK pool and been reallocated.\n\nSet all skip_release_bitmap bits in the common error path of\nmlx5e_xsk_alloc_rx_mpwqe(). This matches mlx5e_alloc_rx_mpwqe(). A\nsuccessful allocation already clears the bitmap after replacing every\nbuffer, so retries become idempotent without changing the success path.\n\nFault injection forced three consecutive failures for one selected MPWQE.\nBoth an early allocation failure and a partial 8-of-16-buffer unwind\nreleased the original 16 XSK buffers only once. Each error left a full\nbitmap, the following NAPI retry skipped the release, and a later\nsuccessful allocation cleared it. A 20-second AF_XDP zero-copy pressure\nrun exercised 1,575,262 buffer allocation failures without invalid\ndescriptors, WQE errors, or kernel warnings.\n\n## Affected\n\n- `Linux >= 4c2a1323680709078736a2886c754004e9fe42e6 < f3a52e2ec2788a7f6b64137985c087188a54ad4f`\n- `Linux >= 4c2a1323680709078736a2886c754004e9fe42e6 < d215d09606b0fcd18ad1eb532995782a21cea49d`\n- `Linux >= 4c2a1323680709078736a2886c754004e9fe42e6 < 867119b4b588037724b85839d534465f0334d9bd`\n- `Linux >= 4c2a1323680709078736a2886c754004e9fe42e6 < 3d73a1164a8c6b4461907a65cb6c022ea4fd39af`\n- `Linux >= 4c2a1323680709078736a2886c754004e9fe42e6 < 63811edf512584c946e5e96b100e9e280703bbb5`\n- `Linux 6.4`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}