{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2026-64567", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-64567", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-08-05T08:08:06.015Z", "updatedAt": "2026-10-19T20:48:42.223Z", "importedAt": "2026-10-24T01:58:25.636Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "btrfs: reject free space cache with more entries than pages", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: reject free space cache with more entries than pages\n\nWhen loading a v1 free space cache, __load_free_space_cache() takes\nnum_entries and num_bitmaps straight from the on-disk\nbtrfs_free_space_header. That header is stored in the tree_root under a key\nwith type 0, which the tree-checker has no case for, so neither count is\nvalidated before the load trusts it.\n\nThe load loops num_entries times and maps the next page whenever the current\none runs out, going through io_ctl_check_crc() -> io_ctl_map_page(), which\ndoes io_ctl->pages[io_ctl->index++]. But pages[] is allocated in\nio_ctl_init() from the cache inode's i_size, not from num_entries:\n\n\tnum_pages = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);\n\tio_ctl->pages = kcalloc(num_pages, sizeof(struct page *), GFP_NOFS);\n\nSo if num_entries claims more records than the pages can hold, io_ctl->index\nruns off the end of pages[]. The write side never hits this because\nio_ctl_add_entry() and io_ctl_add_bitmap() both stop once\nio_ctl->index >= io_ctl->num_pages; the read side just never had the same\ncheck.\n\nTo trigger it, take a clean cache (num_entries = here), set num_entries\nin the header to 0x10000, and fix up the leaf checksum so it still passes\nthe tree-checker. The cache inode has i_size = 65536, so num_pages is 16 and\npages[] is a 16-pointer (kmalloc-128) array. The load now tries to read\n65536 entries, io_ctl->index walks up to 16, and pages[16] is read past the\narray:\n\n BUG: KASAN: slab-out-of-bounds in io_ctl_check_crc (fs/btrfs/free-space-cache.c:420 fs/btrfs/free-space-cache.c:565)\n Read of size 8 at addr ffff88800c833a80 by task kworker/u8:3/58\n io_ctl_check_crc (fs/btrfs/free-space-cache.c:420 fs/btrfs/free-space-cache.c:565)\n __load_free_space_cache (fs/btrfs/free-space-cache.c:655 fs/btrfs/free-space-cache.c:820)\n load_free_space_cache (fs/btrfs/free-space-cache.c:1017)\n caching_thread (fs/btrfs/block-group.c:880)\n btrfs_work_helper (fs/btrfs/async-thread.c:312)\n process_one_work\n worker_thread\n kthread\n ret_from_fork\n\nfree-space-cache.c:420 is io_ctl_map_page(), inlined into io_ctl_check_crc()\nat line 565, which is why that is the frame KASAN names. The out-of-bounds\nslot is then treated as a struct page and handed to crc32c(), so the bad\nread turns into a GP fault.\n\nAdd the missing check to io_ctl_check_crc(), which is where both the entry\nloop and the bitmap loop end up. When num_entries is too large the load now\nfails like any corrupt cache: __load_free_space_cache() drops it and rebuilds\nthe free space from the extent tree, so a valid cache is never rejected.", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "5b0e95bf607ddd59b39f52d3d55e6581c817b530", "status": "affected", "versionType": "git", "lessThan": "8ded74c654a982dc8581a17b0caa7fcedb20de69" }, { "version": "5b0e95bf607ddd59b39f52d3d55e6581c817b530", "status": "affected", "versionType": "git", "lessThan": "c9c38066b6446e83668c041702bb639b0ca49363" }, { "version": "5b0e95bf607ddd59b39f52d3d55e6581c817b530", "status": "affected", "versionType": "git", "lessThan": "094734c7aaa2b36751dc32480a680a4952685e78" }, { "version": "5b0e95bf607ddd59b39f52d3d55e6581c817b530", "status": "affected", "versionType": "git", "lessThan": "33878ba25e2638bc0c61623d7a05c9ca2b74c039" }, { "version": "5b0e95bf607ddd59b39f52d3d55e6581c817b530", "status": "affected", "versionType": "git", "lessThan": "404a0b986e0b6e79738fdf1f0ebbbc43b9acd2a2" }, { "version": "5b0e95bf607ddd59b39f52d3d55e6581c817b530", "status": "affected", "versionType": "git", "lessThan": "5e1b2ca6b34939e70fb0785e8222b53cf060016f" }, { "version": "5b0e95bf607ddd59b39f52d3d55e6581c817b530", "status": "affected", "versionType": "git", "lessThan": "f9fef131fa3f59b857217f522fa5ea430d1b707c" }, { "version": "5b0e95bf607ddd59b39f52d3d55e6581c817b530", "status": "affected", "versionType": "git", "lessThan": "a2d8d5647ed854e38f941741aea45b9eb15a6350" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "3.2", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "3.2" }, { "version": "5.10.265", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.216", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.183", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.148", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.101", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.42", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "7.1.6", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "7.1.*" }, { "version": "7.2", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }