{"cve":"CVE-2026-64307","nvd":{"published":"2026-07-25T10:17:11.800","modified":"2026-10-24T13:10:00.147","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ncrypto: ccp - Do not initialize SNP for ioctl(SNP_CONFIG)\n\nSashiko notes:\n\n> if SEV initialization fails and KVM is actively running normal VMs, could a\n> userspace process trigger this code path via /dev/sev ioctls (e.g.,\n> SEV_PDH_GEN) and zero out MSR_VM_HSAVE_PA globally? Would the next VMRUN\n> execution for an active VM trigger a general protection fault and crash the\n> host?\n\nRefuse to re-try initialization if SNP is not already initialized for\nSNP_CONFIG.\n\nThis is technically an ABI break: before if SNP initialization failed it\ncould be transparently retriggered by this ioctl, and if no VMs were\nrunning, everything worked fine. Hopefully this is enough of a corner case\nthat nobody will notice, but someone does, there are a few options:\n\n* do something like symbol_get() for kvm and refuse to initialize if KVM is\n  loaded\n* check each cpu's HSAVE_PA for non-zero data before re-initializing\n* once initialization has failed, continue to refuse to initialize until\n  the ccp module is unloaded","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":[],"references":["https://git.kernel.org/stable/c/08f0e65e784c4b20e6e620dd4f68d8636073a3d2","https://git.kernel.org/stable/c/20f548cdac94860a164e5ebba4f7e4a01051cb06","https://git.kernel.org/stable/c/345a6e869b33687e9268044bcaeeefd7c61da675","https://git.kernel.org/stable/c/441ea32cf2755a0dc593557056b00b7caa0651f5"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-24T16:53:27.712498749+00:00"},"epss":{"cve":"CVE-2026-64307","score":0.00169,"percentile":0.06249,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}