Vulnerability in Linux

[ Description ]Official description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fill in FileSysIdentifier in FS_POSIX_INFORMATION smb2_get_info_filesystem() reports 56 bytes for FS_POSIX_INFORMATION, that is the whole of FILE_SYSTEM_POSIX_INFO, but never assigns FileSysIdentifier. Those eight bytes go to the client as they are found in the response buffer. The buffer is zeroed on allocation, so a standalone request leaks nothing. A compound request can leak: the offset of the next response is advanced by the length pinned for the previous one, so a reply that was written into the buffer and then dropped in favour of the short error response of smb2_set_err_rsp() stays there, and the next reply is laid over it with only the header cleared. Report the file system id statfs() returned, which is what the field is for. FileSysIdentifier is __le64 and f_fsid is a pair of ints, so assemble the value first, val[0] as the low half, and convert it on the way out.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ Advisories ]Government CERT advisories

• BSI CERT-Bund28 Oct 2026WID-SEC-2026-4224

  Linux Kernel: Multiple vulnerabilities allow an unspecified attack Translated from German

  CVE-2026-99116CVE-2026-99143CVE-2026-99170+113 more CVEs

[ References ]References

• git.kernel.org/stable/c/1d644ab9eac767d52c9b8dc0eb68c0085994d9b6
• git.kernel.org/stable/c/ab057f271ef60ff8163818badc3de75c480eca07
• git.kernel.org/stable/c/beba2ef6f66a71f20531ac70a1acb0b221e362e9
• git.kernel.org/stable/c/cb9fbcaf1f3351bea771eec557fc6c4d2f35762b
• git.kernel.org/stable/c/da2ec27fdd7effbe4c94ec15b6c6a281800c5123
• git.kernel.org/stable/c/db2267b27c054a6c2151ff7fbb67927e784f31d6
• git.kernel.org/stable/c/f5c50f69a70fe22c44a50c869c8cd65fc35a0686