--- id: CVE-2026-64048 title: |- In the Linux kernel, the following vulnerability has been resolved: net/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot On the SMC-D client, slot 0 of ini->ism_dev[]/ini->ism_chid[] is reserved for an SMC-Dv1 device summary: |- In the Linux kernel, the following vulnerability has been resolved: net/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot On the SMC-D client, slot 0 of ini->ism_dev[]/ini->ism_chid[] is reserved 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 - url: >- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64048.json - url: 'https://access.redhat.com/security/cve/CVE-2026-64048' - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2502589' - url: 'https://www.cve.org/CVERecord?id=CVE-2026-64048' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-64048' - url: >- https://lore.kernel.org/linux-cve-announce/2026071907-CVE-2026-64048-a8e3@gregkh/T - url: 'https://access.redhat.com/errata/RHSA-2026:88477' - url: 'https://access.redhat.com/errata/RHSA-2026:57252' - url: 'https://access.redhat.com/errata/RHSA-2026:57253' - url: 'https://access.redhat.com/errata/RHSA-2026:57254' tags: - nvd - cve.org - csaf - vex - red-hat epss: 0.00501 epssPercentile: 0.42713 ingestedAt: '2026-08-23T13:48:05.294Z' vendor: Linux product: Linux affected: - >- Linux >= a7c9c5f4af7f6098da68705fc5d86565d0728ef7 < 903f7688ffeb9b323d70652c01f554bd4ba2a3d6 - >- Linux >= a7c9c5f4af7f6098da68705fc5d86565d0728ef7 < dd2f9dd83c68abd7ba7ded7075290b016cb7ecd0 - >- Linux >= a7c9c5f4af7f6098da68705fc5d86565d0728ef7 < 6927cacf2b10d4fa80c1a2d407512ef9397c59c6 - >- Linux >= a7c9c5f4af7f6098da68705fc5d86565d0728ef7 < d38ba387244e5c5f7db3e11ea98bc2c7beccb0c0 - >- Linux >= a7c9c5f4af7f6098da68705fc5d86565d0728ef7 < 53eb7bd09aace72fa17510d80e0caf5ca058c231 - >- Linux >= a7c9c5f4af7f6098da68705fc5d86565d0728ef7 < afa9036b8c9963947b487c36e332df6a42c96fcb - >- Linux >= a7c9c5f4af7f6098da68705fc5d86565d0728ef7 < 65edb3b0822cfe5041be8fbabebd57e2e5ad9f4e - >- Linux >= a7c9c5f4af7f6098da68705fc5d86565d0728ef7 < 277740023def559a4a2ddc3e8e784ee37a0f16a9 - Linux 5.10 ssvc: exploitation: none automatable: 'yes' technicalImpact: partial timestamp: '2026-10-16T15:35:56.958231Z' patched: - 10base_smtv - enterprise_linux_appstream_v_10 - enterprise_linux_appstream_v_9 - enterprise_linux_baseos_v_10 - enterprise_linux_baseos_v_8 - enterprise_linux_baseos_v_9 - enterprise_linux_codeready_linux_builder_v_10 - enterprise_linux_crb_v_8 - enterprise_linux_codeready_linux_builder_v_9 - enterprise_linux_hidden_v_10 - enterprise_linux_real_time_for_nfv_v_10 - enterprise_linux_nfv_v_8 - enterprise_linux_real_time_for_nfv_v_9 - enterprise_linux_real_time_v_10 - enterprise_linux_rt_v_8 - enterprise_linux_real_time_v_9 cwe: - CWE-476 scores: nvd: 7.5 vendor: 7 --- ## Overview In the Linux kernel, the following vulnerability has been resolved: net/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot On the SMC-D client, slot 0 of ini->ism_dev[]/ini->ism_chid[] is reserved for an SMC-Dv1 device. smc_find_ism_v2_device_clnt() populates V2 entries starting at index 1, so when no V1 device is selected slot 0 is left in its kzalloc()'ed state with ism_dev[0] == NULL and ism_chid[0] == 0. smc_v2_determine_accepted_chid() then matches the peer's CHID against the array starting from index 0 using the CHID alone. A malicious peer replying to a SMC-Dv2-only proposal with d1.chid == 0 matches the empty slot, ini->ism_selected becomes 0, and the subsequent ism_dev[0]->lgr_lock dereference in smc_conn_create() faults at offsetof(struct smcd_dev, lgr_lock) == 0x68: BUG: KASAN: null-ptr-deref in _raw_spin_lock_bh+0x79/0xe0 Write of size 4 at addr 0000000000000068 by task exploit/144 Call Trace: _raw_spin_lock_bh smc_conn_create (net/smc/smc_core.c:1997) __smc_connect (net/smc/af_smc.c:1447) smc_connect (net/smc/af_smc.c:1720) __sys_connect __x64_sys_connect do_syscall_64 Require ism_dev[i] to be non-NULL before accepting a CHID match. ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges. ## Vendor advisories - **RHSA-2026:88477** · Red Hat · fixed in: 10Base-SMTV, Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10), Red Hat Enterprise Linux Hidden (v. 10), Red Hat Enterprise Linux Real Time for NFV (v. 10), … · released 2026-10-23 · [advisory](https://access.redhat.com/errata/RHSA-2026:88477) - **RHSA-2026:57252** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9), Red Hat Enterprise Linux Real Time for NFV (v. 9), Red Hat Enterprise Linux Real Time (v. 9) · released 2026-08-20 · [advisory](https://access.redhat.com/errata/RHSA-2026:57252) - **RHSA-2026:57253** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8) · released 2026-08-20 · [advisory](https://access.redhat.com/errata/RHSA-2026:57253) - **RHSA-2026:57254** · Red Hat · fixed in: Red Hat Enterprise Linux NFV (v. 8), Red Hat Enterprise Linux RT (v. 8) · released 2026-08-20 · [advisory](https://access.redhat.com/errata/RHSA-2026:57254) - **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 9 · updated 2026-10-23 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64048.json)