{"id":"CVE-2026-93186","title":"In the Linux kernel, the following vulnerability has been resolved:\n\ncxl/mbox: Clamp mailbox output allocation to the payload size\n\nCXL_MEM_SEND_COMMAND bounds the user's in.size to the mailbox payload\nsize but leaves out.size unbounded,…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\ncxl/mbox: Clamp mailbox output allocation to the payload size\n\nCXL_MEM_SEND_COMMAND bounds the user's in.size to the mailbox payload\nsize but leaves out.size unbounded,…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 583fa5e71caeb79e04e477e9837e2f7fa53b71e4 < f5d2bbf0300f46307948864fbb97bce5097f4fe2","Linux >= 583fa5e71caeb79e04e477e9837e2f7fa53b71e4 < 31d4841eca7c4b75751ca96d24339e19303337f2","Linux >= 583fa5e71caeb79e04e477e9837e2f7fa53b71e4 < b4e11c731d6bee3b87315e055a1ca417c92dc1fc","Linux >= 583fa5e71caeb79e04e477e9837e2f7fa53b71e4 < 8a13db9f899d149c3aab24abcb668121cfda5a4f","Linux 5.12"],"published":"2026-09-17","updated":"2026-09-17","sourceUpdated":"2026-09-17T17:18:14.683","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-93186","references":[{"url":"https://git.kernel.org/stable/c/31d4841eca7c4b75751ca96d24339e19303337f2","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/8a13db9f899d149c3aab24abcb668121cfda5a4f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b4e11c731d6bee3b87315e055a1ca417c92dc1fc","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f5d2bbf0300f46307948864fbb97bce5097f4fe2","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-17T16:21:47.726Z","epss":0.00186,"epssPercentile":0.08463,"slug":"CVE-2026-93186","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\ncxl/mbox: Clamp mailbox output allocation to the payload size\n\nCXL_MEM_SEND_COMMAND bounds the user's in.size to the mailbox payload\nsize but leaves out.size unbounded, then cxl_mbox_cmd_ctor() calls\nkvzalloc(out.size). A large out.size drives a huge allocation, above\nINT_MAX it WARNs and taints, and with panic_on_warn=1 it panics.\n\nThe transport __cxl_pci_mbox_send_cmd() already clamps the response copy\nto min(out.size, payload_size, device len), so the output buffer is\nnever written beyond payload_size. Clamp the allocation to payload_size\ntoo, matching the RAW path.\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":[]}