libssh2 through 1.11.1, fixed in commit 1762685, contains a pre-authentication denial of service vulnerability in the SSH_MSG_EXT_INFO handler in src/packet.c that allows a malicious SSH server to cause a client CPU exhaustion loop by sending a crafted extension count value. A malicious server can set nr_extensions to 0xFFFFFFFF during key exchange, causing the client to spin in a tight CPU loop for over 60 seconds because return values from _libssh2_get_string() are unchecked and the session timeout does not apply to CPU-bound loops.
| Vendor | Product | Versions |
|---|---|---|
| libssh2 | libssh2 | 0, 1.11.1 |
Downstream vendors/products affected by this vulnerability
| Vendor | Product | Source | Confidence |
|---|---|---|---|
| open source | libssh2 | cert_advisory | 90% |
Updated patch availability to null and added new IoCs related to the vulnerability.
Updated severity to CRITICAL and CVSS score to 9.2, and adjusted tags.
Updated affected versions to include 1.11.1, changed severity to HIGH, added CVE IDs, and provided new patch version 1.11.1-3.
Updated exploit availability to true and added new tags related to DoS and remote attacks.
Updated description with new details, changed severity to HIGH, set CVSS estimate to 7.5, and marked the vulnerability as actively exploited.
Initial creation
