{"cve":"CVE-2026-93787","nvd":{"published":"2026-09-24T17:17:11.363","modified":"2026-10-03T11:17:48.293","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: bound dirent name against end of SMB response in cifs_filldir\n\ncifs_filldir() copies the entry name out of an SMB1 TRANS2_FIND_FIRST /\nFIND_NEXT response using a length (de.namelen) supplied by the server.\nThe kmalloc'd SMB response buffer is bounded, but nothing checks that\nde.name + de.namelen still lies inside that buffer before the eventual\nfilldir64() -> verify_dirent_name() -> memchr() reads namelen bytes.\n\nA hostile SMB1 server that returns an oversized FileNameLength in a\ndirectory entry therefore causes memchr() to read past the end of the\nresponse slab buffer. Reachable from any user who can list a directory\non a CIFS mount served by an attacker-controlled server (getdents64()\non the mounted directory):\n\n  BUG: KASAN: slab-out-of-bounds in memchr+0x71/0x80\n  Read of size 1 at addr ffff88800e0640cc by task poc/115\n  Call Trace:\n   dump_stack_lvl+0x64/0x80\n   print_report+0xce/0x620\n   kasan_report+0xec/0x120\n   memchr+0x71/0x80\n   filldir64+0x4c/0x6a0\n   cifs_filldir.constprop.0+0x9bb/0x1e00\n   cifs_readdir+0x2101/0x3380\n   iterate_dir+0x19c/0x520\n   __x64_sys_getdents64+0x126/0x210\n   do_syscall_64+0x107/0x5a0\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nPass the end-of-response pointer down to cifs_filldir() and reject\nentries whose name would extend past that boundary.\n\nThis bug was discovered by Artiphishell's vTriage pipeline, which\ngenerated a userspace reproducer (an emulated hostile SMB1 server plus\na getdents64() client) that reliably triggers the KASAN report on an\nunpatched kernel. The fix below was drafted with the Claude coding\nassistant; a userspace reproducer is available on request.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H","score":8.1},"cwes":[],"references":["https://git.kernel.org/stable/c/03003506c86f90312b0966283662c42fcab66e4b","https://git.kernel.org/stable/c/4cb3d79beee0fecc739ce07af915d503f29ae557","https://git.kernel.org/stable/c/6e3b965267b7313903baba2739992b1e2e92d540","https://git.kernel.org/stable/c/cf87ef1e62ed31a439064cef69d6eec38c68bd92","https://git.kernel.org/stable/c/f8cf09a53a0dc1da298e9dd0ba5f21710cf119d6"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:56:02.509636177+00:00"},"epss":{"cve":"CVE-2026-93787","score":0.00344,"percentile":0.27678,"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."]}