OpenSSH versions prior to 10.3 incorrectly interpret any listing of an ECDSA algorithm in PubkeyAcceptedAlgorithms or HostbasedAcceptedAlgorithms as an instruction to accept all ECDSA algorithms. This misinterpretation can expose sensitive cryptographic information, potentially allowing a malicious actor to learn details about accepted key types or infer configuration settings. The weakness is rooted in cryptographic confusion and unexpected behavior described by CWE-115 and CWE-670.

The vulnerability affects the OpenBSD OpenSSH implementation. All releases before 10.3 are impacted, including OpenSSH 10.2 and earlier. No specific patch versions are listed beyond the recommendation to upgrade to 10.3 or newer.

The CVSS score of 3.1 indicates a low overall severity, and the EPSS (exploit probability) score is below 1%, suggesting a very low likelihood of exploitation in the wild. The vulnerability is not currently listed in the CISA known exploited vulnerabilities catalog. The attack vector is inferred to be remote via an SSH connection, where an attacker could craft or alter the algorithm list in a client or server configuration to trigger the information disclosure. Because no immediate exploitation code is documented, the risk remains low but the potential for sensitive data exposure exists.