{"cve":"CVE-2026-63817","nvd":{"published":"2026-07-19T12:16:54.757","modified":"2026-08-17T05:17:19.003","status":"Awaiting Analysis","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: validate compress cache inode only when enabled\n\nF2FS_COMPRESS_INO() uses NM_I(sbi)->max_nid as the synthetic inode\nnumber for the compressed page cache inode. That inode only exists when\nthe compress_cache mount option is enabled.\n\nWhen compress_cache is disabled, max_nid is outside the valid inode\nrange. A corrupted directory entry that points to ino == max_nid should\ntherefore be rejected by f2fs_check_nid_range(). However, is_meta_ino()\ncurrently treats F2FS_COMPRESS_INO() as a meta inode unconditionally,\nso f2fs_iget() bypasses do_read_inode() and its nid range check, and\ninstantiates a fake internal inode instead.\n\nGate the compressed cache inode case on COMPRESS_CACHE, matching\nf2fs_init_compress_inode(). With compress_cache disabled, ino ==\nmax_nid now follows the normal inode path and is rejected as an\nout-of-range nid.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":[],"references":["https://git.kernel.org/stable/c/0969926d987bbde9a1aa49da317582ba37095805","https://git.kernel.org/stable/c/13e4b59d3a9413f66f116fa6c4828519b960a5ea","https://git.kernel.org/stable/c/16161444c30d8dff9428abbae42b72ce4e32a932","https://git.kernel.org/stable/c/29115b8c9172d34e67ab26cc4f6c209b7a236d7a","https://git.kernel.org/stable/c/5073c66a96a9c23c0c2533ed4ed06e42f9021208"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:45:36.895656543+00:00"},"epss":{"cve":"CVE-2026-63817","score":0.00134,"percentile":0.02884,"date":"2026-11-01"},"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."]}