{"cve":"CVE-2026-80807","nvd":{"published":"2026-09-04T16:18:07.810","modified":"2026-10-19T09:17:15.380","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnilfs2: reject invalid block index in GC ioctl\n\nSyzbot reported list corruption caused by a double list_add_tail() call on\nbh->b_assoc_buffers within nilfs_lookup_dirty_data_buffers().\n\nAnalysis revealed that the root cause was the insertion of a page/folio\nwith a page index of ULONG_MAX into the page cache via the GC ioctl.\nfilemap_get_folios_tag(), called by nilfs_lookup_dirty_data_buffers(),\nrepeatedly detects a dirty folio with a page index of ULONG_MAX due to\nindex wrap-around, leading to duplicate processing of dirty buffers.\n\nAs a preparatory step, the GC ioctl loads the page/folio of the block to\nbe moved during GC and inserts it into the page cache based on information\nin the nilfs_vdesc structure passed as an argument.  Normally, this does\nnot cause issues because the user-space GC library configures the\nnilfs_vdesc structure properly.  However, since there is no range check on\nthe parameters determining the page index, a request with artificially\ncrafted parameters -- such as those generated by Syzbot -- can result in a\npage/folio being inserted with a page index of ULONG_MAX, triggering the\nabove problem.\n\nThis resolves the issue by checking the ranges of 'vd_offset' and\n'vd_vblocknr' in the nilfs_vdesc structure that determine the page index,\nthereby preventing the invalid page/folio insertions.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/3bd064ccc70b85f9a3d53aece29dc8473be5a226","https://git.kernel.org/stable/c/68aa9ab6f8f2895713aa6ddf781463ed8ea5ba44","https://git.kernel.org/stable/c/898404cdf882d7b54f1132f75570984ca3214796","https://git.kernel.org/stable/c/a1735eae55448bc79c2da6593455791e886f6ed8","https://git.kernel.org/stable/c/a5e776e2937581d67ec5b9b4d27b0f70d7baa6b1"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:52:03.409947763+00:00"},"epss":{"cve":"CVE-2026-80807","score":0.00201,"percentile":0.09834,"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."]}