Integer Overflow Vulnerability in OpenSSH Affects Key Parsing

CVE-2019-16905

Summary

OpenSSH versions 7.7 through 7.9 and 8.x prior to version 8.1 may be prone to an integer overflow vulnerability when compiled with an experimental XMSS key type. This issue occurs during the pre-authentication phase and arises from an error in the XMSS key parsing algorithm, potentially leading to memory corruption and enabling local code execution. The XMSS implementation remains experimental across all released OpenSSH versions, and there is no officially supported method to activate it in portable builds.

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