{"id":"CVE-2026-64048","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot\n\nOn the SMC-D client, slot 0 of ini->ism_dev[]/ini->ism_chid[] is\nreserved for an SMC-Dv1 device","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot\n\nOn the SMC-D client, slot 0 of ini->ism_dev[]/ini->ism_chid[] is\nreserved for an SMC-Dv1 device. smc_f…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","published":"2026-07-19","updated":"2026-08-23","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-64048","references":[{"url":"https://git.kernel.org/stable/c/277740023def559a4a2ddc3e8e784ee37a0f16a9","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/53eb7bd09aace72fa17510d80e0caf5ca058c231","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/65edb3b0822cfe5041be8fbabebd57e2e5ad9f4e","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/6927cacf2b10d4fa80c1a2d407512ef9397c59c6","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/903f7688ffeb9b323d70652c01f554bd4ba2a3d6","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/afa9036b8c9963947b487c36e332df6a42c96fcb","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d38ba387244e5c5f7db3e11ea98bc2c7beccb0c0","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/dd2f9dd83c68abd7ba7ded7075290b016cb7ecd0","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd"],"epss":0.00501,"epssPercentile":0.41777,"ingestedAt":"2026-08-23T13:48:05.294Z","slug":"CVE-2026-64048","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot\n\nOn the SMC-D client, slot 0 of ini->ism_dev[]/ini->ism_chid[] is\nreserved for an SMC-Dv1 device. smc_find_ism_v2_device_clnt()\npopulates V2 entries starting at index 1, so when no V1 device is\nselected slot 0 is left in its kzalloc()'ed state with ism_dev[0] ==\nNULL and ism_chid[0] == 0.\n\nsmc_v2_determine_accepted_chid() then matches the peer's CHID against\nthe array starting from index 0 using the CHID alone. A malicious\npeer replying to a SMC-Dv2-only proposal with d1.chid == 0 matches\nthe empty slot, ini->ism_selected becomes 0, and the subsequent\nism_dev[0]->lgr_lock dereference in smc_conn_create() faults at\noffsetof(struct smcd_dev, lgr_lock) == 0x68:\n\n  BUG: KASAN: null-ptr-deref in _raw_spin_lock_bh+0x79/0xe0\n  Write of size 4 at addr 0000000000000068 by task exploit/144\n  Call Trace:\n   _raw_spin_lock_bh\n   smc_conn_create (net/smc/smc_core.c:1997)\n   __smc_connect (net/smc/af_smc.c:1447)\n   smc_connect (net/smc/af_smc.c:1720)\n   __sys_connect\n   __x64_sys_connect\n   do_syscall_64\n\nRequire ism_dev[i] to be non-NULL before accepting a CHID match.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}