{"cve":"CVE-2026-89656","nvd":{"published":"2026-09-11T20:19:51.813","modified":"2026-10-19T09:18:03.343","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nlibceph: reject buckets with mismatched CRUSH ids\n\ncrush_decode() stores bucket data by array slot, and the mapper later\nderives the per-bucket workspace index from the decoded bucket id. A\nmalformed map can therefore make one bucket reuse another bucket's\nworkspace by encoding an id different from -1 - slot.\n\nFor uniform buckets, the second replica selection expands the source\nbucket's permutation into that aliased workspace buffer. If the source\nbucket is larger than the aliased bucket, the write runs past the smaller\npermutation array and can escape the kvmalloc'd CRUSH workspace. KASAN\nreports a slab OOB write of 4 bytes in bucket_perm_choose().\n\nReject buckets whose encoded id does not match their array slot. Valid\nCRUSH maps already use the canonical negative id corresponding to the\nbucket slot, so this restores the invariant expected by\nwork->work[-1 - in->id] without changing valid map behavior.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":[],"references":["https://git.kernel.org/stable/c/00562ccd4e88d092b9b851df50fad20442bfeb24","https://git.kernel.org/stable/c/3516a4131c4e45d62ee4e42e82c36930e8c1fbbd","https://git.kernel.org/stable/c/3cde4a8302301679937474a5f7a851394cc1bd11","https://git.kernel.org/stable/c/4aeb93daadf388e72073abc204312dd364eeb30a","https://git.kernel.org/stable/c/6e5c6ce252b1eccfd41670a5cf95ab44f7ba7022"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:53:43.293028046+00:00"},"epss":{"cve":"CVE-2026-89656","score":0.00514,"percentile":0.43523,"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."]}