{"cve":"CVE-2026-53027","nvd":{"published":"2026-06-24T17:17:14.087","modified":"2026-10-30T13:19:09.193","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nfs/ntfs3: fix missing run load for vcn0 in attr_data_get_block_locked()\n\nWhen a compressed or sparse attribute has its clusters frame-aligned,\nvcn is rounded down to the frame start using cmask, which can result\nin vcn != vcn0. In this case, vcn and vcn0 may reside in different\nattribute segments.\n\nThe code already handles the case where vcn is in a different segment\nby loading its runs before allocation. However, it fails to load runs\nfor vcn0 when vcn0 resides in a different segment than vcn. This causes\nrun_lookup_entry() to return SPARSE_LCN for vcn0 since its segment was\nnever loaded into the in-memory run list, triggering the WARN_ON(1).\n\nFix this by adding a missing check for vcn0 after the existing vcn\nsegment check. If vcn0 falls outside the current segment range\n[svcn, evcn1), find and load the attribute segment containing vcn0\nbefore performing the run lookup.\n\nThe following scenario triggers the bug:\n  attr_data_get_block_locked()\n    vcn = vcn0 & cmask        <- vcn != vcn0 after frame alignment\n    load runs for vcn segment <- vcn0 segment not loaded!\n    attr_allocate_clusters()  <- allocation succeeds\n    run_lookup_entry(vcn0)    <- vcn0 not in run -> SPARSE_LCN\n    WARN_ON(1)                <- bug fires here!","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/08fad5d5a26cc55c0ecb68ac59ba3be5e31f4147","https://git.kernel.org/stable/c/2b4ae1ce613ade8a7e118fba4a5a77cd23e97e54","https://git.kernel.org/stable/c/543093f65318d012850e548b241f85381b14d643","https://git.kernel.org/stable/c/d68a14450783ecc5fddae957ac4e1c546dfcfb73","https://git.kernel.org/stable/c/d7ea8495fd307b58f8867acd81a1b40075b1d3ba"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-30T13:47:47.119061695+00:00"},"epss":{"cve":"CVE-2026-53027","score":0.00122,"percentile":0.0195,"date":"2026-10-30"},"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."]}