{"id":"CVE-2026-64048","state":"PUBLISHED","title":"net/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot","description":"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_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.","publishedAt":"2026-07-19T15:39:32.664Z","updatedAt":"2026-10-19T20:28:10.855Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a7c9c5f4af7f6098da68705fc5d86565d0728ef7","status":"affected","lessThan":"903f7688ffeb9b323d70652c01f554bd4ba2a3d6","versionType":"git"},{"version":"a7c9c5f4af7f6098da68705fc5d86565d0728ef7","status":"affected","lessThan":"dd2f9dd83c68abd7ba7ded7075290b016cb7ecd0","versionType":"git"},{"version":"a7c9c5f4af7f6098da68705fc5d86565d0728ef7","status":"affected","lessThan":"6927cacf2b10d4fa80c1a2d407512ef9397c59c6","versionType":"git"},{"version":"a7c9c5f4af7f6098da68705fc5d86565d0728ef7","status":"affected","lessThan":"d38ba387244e5c5f7db3e11ea98bc2c7beccb0c0","versionType":"git"},{"version":"a7c9c5f4af7f6098da68705fc5d86565d0728ef7","status":"affected","lessThan":"53eb7bd09aace72fa17510d80e0caf5ca058c231","versionType":"git"},{"version":"a7c9c5f4af7f6098da68705fc5d86565d0728ef7","status":"affected","lessThan":"afa9036b8c9963947b487c36e332df6a42c96fcb","versionType":"git"},{"version":"a7c9c5f4af7f6098da68705fc5d86565d0728ef7","status":"affected","lessThan":"65edb3b0822cfe5041be8fbabebd57e2e5ad9f4e","versionType":"git"},{"version":"a7c9c5f4af7f6098da68705fc5d86565d0728ef7","status":"affected","lessThan":"277740023def559a4a2ddc3e8e784ee37a0f16a9","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/smc/af_smc.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.10","versionType":"semver"},{"version":"5.10.266","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.217","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.175","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.142","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.92","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.34","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.11","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/smc/af_smc.c"]}],"references":["https://git.kernel.org/stable/c/903f7688ffeb9b323d70652c01f554bd4ba2a3d6","https://git.kernel.org/stable/c/dd2f9dd83c68abd7ba7ded7075290b016cb7ecd0","https://git.kernel.org/stable/c/6927cacf2b10d4fa80c1a2d407512ef9397c59c6","https://git.kernel.org/stable/c/d38ba387244e5c5f7db3e11ea98bc2c7beccb0c0","https://git.kernel.org/stable/c/53eb7bd09aace72fa17510d80e0caf5ca058c231","https://git.kernel.org/stable/c/afa9036b8c9963947b487c36e332df6a42c96fcb","https://git.kernel.org/stable/c/65edb3b0822cfe5041be8fbabebd57e2e5ad9f4e","https://git.kernel.org/stable/c/277740023def559a4a2ddc3e8e784ee37a0f16a9"],"weaknesses":["CWE-476"],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/64xxx/CVE-2026-64048.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64048","state":"PUBLISHED","datePublished":"2026-07-19T15:39:32.664Z","dateUpdated":"2026-10-19T20:28:10.855Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T07:54:57.029Z"},"containers":{"cna":{"title":"net/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot","descriptions":[{"lang":"en","value":"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_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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a7c9c5f4af7f6098da68705fc5d86565d0728ef7","status":"affected","lessThan":"903f7688ffeb9b323d70652c01f554bd4ba2a3d6","versionType":"git"},{"version":"a7c9c5f4af7f6098da68705fc5d86565d0728ef7","status":"affected","lessThan":"dd2f9dd83c68abd7ba7ded7075290b016cb7ecd0","versionType":"git"},{"version":"a7c9c5f4af7f6098da68705fc5d86565d0728ef7","status":"affected","lessThan":"6927cacf2b10d4fa80c1a2d407512ef9397c59c6","versionType":"git"},{"version":"a7c9c5f4af7f6098da68705fc5d86565d0728ef7","status":"affected","lessThan":"d38ba387244e5c5f7db3e11ea98bc2c7beccb0c0","versionType":"git"},{"version":"a7c9c5f4af7f6098da68705fc5d86565d0728ef7","status":"affected","lessThan":"53eb7bd09aace72fa17510d80e0caf5ca058c231","versionType":"git"},{"version":"a7c9c5f4af7f6098da68705fc5d86565d0728ef7","status":"affected","lessThan":"afa9036b8c9963947b487c36e332df6a42c96fcb","versionType":"git"},{"version":"a7c9c5f4af7f6098da68705fc5d86565d0728ef7","status":"affected","lessThan":"65edb3b0822cfe5041be8fbabebd57e2e5ad9f4e","versionType":"git"},{"version":"a7c9c5f4af7f6098da68705fc5d86565d0728ef7","status":"affected","lessThan":"277740023def559a4a2ddc3e8e784ee37a0f16a9","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/smc/af_smc.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.10","versionType":"semver"},{"version":"5.10.266","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.217","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.175","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.142","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.92","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.34","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.11","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/smc/af_smc.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/903f7688ffeb9b323d70652c01f554bd4ba2a3d6"},{"url":"https://git.kernel.org/stable/c/dd2f9dd83c68abd7ba7ded7075290b016cb7ecd0"},{"url":"https://git.kernel.org/stable/c/6927cacf2b10d4fa80c1a2d407512ef9397c59c6"},{"url":"https://git.kernel.org/stable/c/d38ba387244e5c5f7db3e11ea98bc2c7beccb0c0"},{"url":"https://git.kernel.org/stable/c/53eb7bd09aace72fa17510d80e0caf5ca058c231"},{"url":"https://git.kernel.org/stable/c/afa9036b8c9963947b487c36e332df6a42c96fcb"},{"url":"https://git.kernel.org/stable/c/65edb3b0822cfe5041be8fbabebd57e2e5ad9f4e"},{"url":"https://git.kernel.org/stable/c/277740023def559a4a2ddc3e8e784ee37a0f16a9"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - The fault is triggered while processing a malicious CLC ACCEPT message received from a remote TCP peer during the SMC-D handshake; the attacker controls the server response over the network.\nAC:L - Once a victim with SMC-Dv2 hardware initiates an SMC connection, a malicious peer can reliably send `d1.chid == 0` in the CLC ACCEPT to match the empty reserved slot 0 without races or special timing.\nPR:N - No local privileges are required on the victim host; an unauthenticated remote attacker operating a malicious SMC server can crash connecting clients, and unprivileged users can create SMC sockets without capability checks.\nUI:N - Exploitation requires only that a victim application initiate a normal outbound SMC connection to the attacker's server, which occurs automatically in enterprise middleware without per-connection user action.\nS:U - The vulnerability causes a kernel crash on the victim host but does not cross a security boundary such as VM escape or sandbox breakout.\nC:N - The bug is a null pointer dereference when taking `ism_dev[0]->lgr_lock`; it causes an immediate kernel fault with no information disclosure.\nI:N - The attempted write at address 0x68 is a spinlock operation on a NULL `smcd_dev` pointer, not a controlled or arbitrary memory modification primitive.\nA:H - A successful trigger causes a kernel null pointer dereference (KASAN-reported oops/panic), crashing the affected system or at minimum the connecting process's kernel context."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-23T12:45:32.597Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"5.10.266"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"5.15.217"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"6.1.175"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"6.6.142"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"6.12.92"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"6.18.34"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"7.0.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"7.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-64048","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-10-16T15:35:56.958231Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-476","lang":"en","type":"CWE","description":"CWE-476 NULL Pointer Dereference"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T20:28:10.855Z"}}]}}}