A flaw was found in libssh. A remote attacker, by controlling client configuration files or known_hosts files, could craft specific hostnames that when processed by the match_pattern() function can lead to inefficient regular expression backtracking. This can cause timeouts and resource exhaustion, resulting in a Denial of Service (DoS) for the client.
Weakness
The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Libssh | Libssh | * | 0.11.3 (including) |
| Enterprise_linux | Redhat | 9.0 (including) | 9.0 (including) |
| Enterprise_linux | Redhat | 10.0 (including) | 10.0 (including) |
| Red Hat Enterprise Linux 10 | RedHat | libssh-0:0.12.0-2.el10 | * |
| Red Hat Enterprise Linux 9 | RedHat | libssh-0:0.10.4-18.el9 | * |
| Red Hat Enterprise Linux 9 | RedHat | libssh-0:0.10.4-18.el9 | * |
| Libssh | Ubuntu | devel | * |
| Libssh | Ubuntu | esm-infra-legacy/xenial | * |
| Libssh | Ubuntu | esm-infra/bionic | * |
| Libssh | Ubuntu | esm-infra/focal | * |
| Libssh | Ubuntu | esm-infra/xenial | * |
| Libssh | Ubuntu | jammy | * |
| Libssh | Ubuntu | noble | * |
| Libssh | Ubuntu | questing | * |
| Libssh | Ubuntu | upstream | * |