{"cve":"CVE-2026-93813","nvd":{"published":"2026-09-24T17:17:14.763","modified":"2026-10-03T11:17:51.120","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: tree-checker: validate INODE_REF's namelen\n\n[BUG]\nA crafted btrfs image can trigger the following crash:\n\n  BUG: unable to handle page fault for address: ffffd1dc42884000\n  #PF: supervisor write access in kernel mode\n  #PF: error_code(0x0002) - not-present page\n  CPU: 9 UID: 0 PID: 1034 Comm: poc Not tainted 7.1.0-rc4-custom+ #383 PREEMPT(full)  46af0a92938a63be7132e0dfd71e62327c51d5c2\n  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 02/02/2022\n  RIP: 0010:memcpy+0xc/0x10\n  Call Trace:\n   <TASK>\n   read_extent_buffer+0xe4/0x100 [btrfs 3cf0785dd58fec8c5ff84633b772f17ce1f92a8f]\n   btrfs_get_name+0x15e/0x1e0 [btrfs 3cf0785dd58fec8c5ff84633b772f17ce1f92a8f]\n   reconnect_path+0x165/0x390\n   exportfs_decode_fh_raw+0x337/0x400\n   ? drop_caches_sysctl_handler+0xb0/0xb0\n   </TASK>\n  ---[ end trace 0000000000000000 ]---\n  RIP: 0010:memcpy+0xc/0x10\n  Kernel panic - not syncing: Fatal exception\n\n[CAUSE]\nTThe crafted image has the following corrupted INODE_REF item:\n\n         item 9 key (258 INODE_REF 257) itemoff 11544 itemsize 4106\n         \tindex 2 namelen 4096 name: d\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\\000\n\nThe itemsize matches the namelen, but the namelen is 4096, way larger\nthan normal name length limit (BTRFS_NAME_LEN, 255).\n\nMeanwhile the memory of the @name is only 255 byte sized, this will cause\nout-of-boundary access, and cause the above crash.\n\n[FIX]\nAdd extra namelen verification for INODE_REF, just like what we have\ndone in ROOT_REF checks.\n\nNow the crafted image can be rejected gracefully:\n\n BTRFS critical (device dm-2): corrupt leaf: root=5 block=30572544 slot=14 ino=259, invalid inode ref name length, has 4096 expect [1, 255]\n BTRFS error (device dm-2): read time tree block corruption detected on logical 30572544 mirror 2\n\n[ Rebase, add a Link: tag, add an simple cause analyze ]","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/3dc22abc21f5892406c09202fa2627196cc96967","https://git.kernel.org/stable/c/4cb41f07685f88ec724a375883bb0c731db8f6eb","https://git.kernel.org/stable/c/509d6a4d889e425f305461d8323a7b39ca6c121c","https://git.kernel.org/stable/c/60078a3e25c09d9d8fba828b0d81bb33e449a1b2","https://git.kernel.org/stable/c/8f75c19892263bc0555fba922aefe103e841e86d"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:56:02.509636177+00:00"},"epss":{"cve":"CVE-2026-93813","score":0.00129,"percentile":0.02539,"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."]}