In libssh2 v1.9.0 and earlier versions, the SSH_MSG_DISCONNECT logic in packet.c has an integer overflow in a bounds check, enabling an attacker to specify an arbitrary (out-of-bounds) offset for a subsequent memory read. A crafted SSH server may be able to disclose sensitive information or cause a denial of service condition on the client system when a user connects to the server.

References

• https://nvd.nist.gov/vuln/detail/CVE-2019-17498
• libssh2/libssh2@1c6fa92
• libssh2/libssh2@dedcbd1
• https://blog.semmle.com/libssh2-integer-overflow-CVE-2019-17498/
• https://github.com/kevinbackhouse/SecurityExploits/tree/8cbdbbe6363510f7d9ceec685373da12e6fc752d/libssh2/out_of_bounds_read_disconnect_CVE-2019-17498
• https://github.com/libssh2/libssh2/blob/42d37aa63129a1b2644bf6495198923534322d64/src/packet.c#L480
• https://lists.debian.org/debian-lts-announce/2019/11/msg00010.html
• https://lists.debian.org/debian-lts-announce/2021/12/msg00013.html
• https://lists.fedoraproject.org/archives/list/[email protected]/message/22H4Q5XMGS3QNSA7OCL3U7UQZ4NXMR5O/
• https://lists.fedoraproject.org/archives/list/[email protected]/message/TY7EEE34RFKCTXTMBQQWWSLXZWSCXNDB/
• http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00026.html
• https://security.netapp.com/advisory/ntap-20220909-0004/
• http://packetstormsecurity.com/files/172835/libssh2-1.9.0-Out-Of-Bounds-Read.html
• https://lists.debian.org/debian-lts-announce/2023/09/msg00006.html