{"id":"CVE-2026-99192","title":"net: bcmgenet: unshare the skb before writing the control block","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: bcmgenet: unshare the skb before writing the control block\n\nbcmgenet stores first_cb, last_cb and bytes_sent in the skb control\nblock and reads them back on comple…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= f48bed16a756f5bc0244acd581f61968f7d7c2a4 < 40c04abcbc34e3afe338f41dae851ecbd72852ac","Linux >= f48bed16a756f5bc0244acd581f61968f7d7c2a4 < 7939ad3b4db9eadf45a64f0524f38337a9494672","Linux >= f48bed16a756f5bc0244acd581f61968f7d7c2a4 < 89771ce4f8f67dcffae561b2ccac95c0f6e3aa01","Linux fb4ca2b4bc6712a6ad635df5b9b41131846589f9","Linux >= 3.16.50 < 3.17","Linux 4.13"],"published":"2026-10-28","updated":"2026-10-28","sourceUpdated":"2026-10-28T10:35:48.686Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-99192","references":[{"url":"https://git.kernel.org/stable/c/40c04abcbc34e3afe338f41dae851ecbd72852ac"},{"url":"https://git.kernel.org/stable/c/7939ad3b4db9eadf45a64f0524f38337a9494672"},{"url":"https://git.kernel.org/stable/c/89771ce4f8f67dcffae561b2ccac95c0f6e3aa01"}],"tags":["cve.org"],"ingestedAt":"2026-10-28T11:09:40.373Z","slug":"CVE-2026-99192","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet: bcmgenet: unshare the skb before writing the control block\n\nbcmgenet stores first_cb, last_cb and bytes_sent in the skb control\nblock and reads them back on completion to free the skb and credit BQL.\nether_setup() leaves IFF_TX_SKB_SHARING set, so the stack can resubmit\na shared skb that is still in the ring. The next transmit overwrites\nlast_cb, so the earlier slots complete without crediting their bytes\nand BQL stalls the queue until the watchdog resets it.\n\nUnshare the skb before writing the control block.\n\nReproduce with pktgen in clone_skb mode, which hands the driver the same\nskb while earlier copies are still in the ring:\n\n  modprobe pktgen\n  pg=/proc/net/pktgen\n  echo \"add_device eth0\" > $pg/kpktgend_0\n  echo \"dst_mac AA:BB:CC:DD:EE:FF\" > $pg/eth0\n  echo \"dst 192.0.2.1\" > $pg/eth0\n  echo \"clone_skb 8\" > $pg/eth0\n  echo \"count 0\" > $pg/eth0\n  echo start > $pg/pgctrl &\n  sleep 5\n  echo stop > $pg/pgctrl\n  wait\n  cat /sys/class/net/eth0/queues/tx-0/byte_queue_limits/inflight\n\ninflight stays nonzero on the now idle queue. clone_skb 0 leaves it at\nzero.\n\n## Affected\n\n- `Linux >= f48bed16a756f5bc0244acd581f61968f7d7c2a4 < 40c04abcbc34e3afe338f41dae851ecbd72852ac`\n- `Linux >= f48bed16a756f5bc0244acd581f61968f7d7c2a4 < 7939ad3b4db9eadf45a64f0524f38337a9494672`\n- `Linux >= f48bed16a756f5bc0244acd581f61968f7d7c2a4 < 89771ce4f8f67dcffae561b2ccac95c0f6e3aa01`\n- `Linux fb4ca2b4bc6712a6ad635df5b9b41131846589f9`\n- `Linux >= 3.16.50 < 3.17`\n- `Linux 4.13`\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":[]}