{"cve":"CVE-2026-46159","nvd":{"published":"2026-05-28T10:16:31.553","modified":"2026-10-15T02:19:47.090","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix btrfs_ioctl_space_info() slot_count TOCTOU which can lead to info-leak\n\nbtrfs_ioctl_space_info() has a TOCTOU race between two passes over the\nblock group RAID type lists. The first pass counts entries to determine\nthe allocation size, then the second pass fills the buffer. The\ngroups_sem rwlock is released between passes, allowing concurrent block\ngroup removal to reduce the entry count.\n\nWhen the second pass fills fewer entries than the first pass counted,\ncopy_to_user() copies the full alloc_size bytes including trailing\nuninitialized kmalloc bytes to userspace.\n\nFix by copying only total_spaces entries (the actually-filled count from\nthe second pass) instead of alloc_size bytes, and switch to kzalloc so\nany future copy size mismatch cannot leak heap data.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H","score":4.7},"cwes":["CWE-367"],"references":["https://git.kernel.org/stable/c/4fdc6ee0802121d9cd96b8d085e589f51e5a4ec3","https://git.kernel.org/stable/c/5d12e0ab009ade48c1bff9324fd9bea2c773d088","https://git.kernel.org/stable/c/973e57c726c1f8e77259d1c8e519519f1e9aea77","https://git.kernel.org/stable/c/d09d67d5de577cedae3de9497dff217e0ac8b641","https://git.kernel.org/stable/c/d69a4a6813fdba7c4cc3695a7e843842b240790d"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:36:28.938604137+00:00"},"epss":{"cve":"CVE-2026-46159","score":0.00098,"percentile":0.00745,"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."]}