Unauthenticated SSH access via stale success return
Published May 26, 2023 · Updated Nov 3, 2025
Improper authentication in libssh 0.9.0 through 0.9.6 and 0.10.0 through 0.10.4 allows remote attackers to access SSH accounts. The pki_verify_data_signature path overwrites rc with SSH_OK before cryptographic verification, so allocation or initialization errors return success. The bypass requires the OpenSSL backend and a reachable memory-allocation failure; Ed25519 on 0.9.x follows an unaffected path.
Summary
What happened
Improper authentication in libssh 0.9.0 through 0.9.6 and 0.10.0 through 0.10.4 allows remote attackers to access SSH accounts. The pki_verify_data_signature path overwrites rc with SSH_OK before cryptographic verification, so allocation or initialization errors return success. The bypass requires the OpenSSL backend and a reachable memory-allocation failure; Ed25519 on 0.9.x follows an unaffected path.
The record
- CVE
- CVE-2023-2283
- Published
- May 26, 2023
- Updated
- Nov 3, 2025
- Vendor
- libssh
- Product
- libssh
- Classifications
- CWE-287, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 26, 2023CVE publishedPublication date reported by the CVE source.
- Nov 3, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=libssh-2
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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