The russh SSH library versions from 0.34.0 up to but not including 0.61.0 contain a vulnerability where SSH message fields are allocated before their size is checked. This allows a peer to send oversized or highly fragmented algorithm name-lists during the SSH key exchange, causing excessive memory allocation. The issue is fixed in version 0.61.0 by rejecting name-lists longer than 16 KiB or containing more than 1,024 entries before processing.