published October 6, 2026
In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix server->total_read for compound encrypted PDUs
In receive_encrypted_standard(), server->total_read is left at the
full decrypted frame size when walking sub-PDUs of a compound encrypted
frame. As a result, cifs_handle_standard() passes this full size
to smb2_check_message(), causing the PDU length guards to incorrectly
validate the entire compound frame instead of the current sub-PDU.
This allows truncated non-last sub-PDUs to bypass length validation,
leading to out-of-bounds reads in smb2_get_data_area_len().
Fix this by setting server->total_read to the true length of the
current sub-PDU: next_cmd for non-last sub-PDUs, and the remaining
pdu_length for the last one.