{"cve":"CVE-2026-72292","nvd":{"published":"2026-08-15T06:22:01.377","modified":"2026-08-17T06:18:32.017","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: s390: Initialize KVM_S390_GET_CMMA_BITS memory\n\nkvm_s390_get_cmma_bits() allocates its output buffer with vmalloc(),\nwhich does not zero the returned pages:\n\n\tvalues = vmalloc(args->count);\n\nIn the non-peek (migration) path, dat_get_cmma() reports a byte count\nspanning from the first to the last dirty page, but __dat_get_cmma_pte()\nwrites values[gfn - start] only for pages whose CMMA dirty bit is set.\nThe walk uses DAT_WALK_IGN_HOLES, so clean and unmapped pages that lie\nbetween two dirty pages within the reported span are visited but never\nstore their byte.  Those gaps (up to KVM_S390_MAX_BIT_DISTANCE pages\neach) stay uninitialized yet fall inside [0, count) and are copied out\nby copy_to_user(), disclosing stale kernel memory to user space.\n\nBefore the switch to the new gmap implementation the buffer was fully\npopulated for every gfn in the span, so no uninitialized bytes were\nexposed; the dirty-only walk introduced the leak.\n\nUse vzalloc() so the gaps read back as zero.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/a4a19941ccb2164edc3491faa5ac5df82e94b363","https://git.kernel.org/stable/c/c7dda3d0f869dc97223448a06c9a2e5235928e48"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:48:17.459049833+00:00"},"epss":{"cve":"CVE-2026-72292","score":0.00198,"percentile":0.09574,"date":"2026-10-31"},"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."]}