Описание
A flaw was found in libssh versions built with OpenSSL versions older than 3.0, specifically in the ssh_kdf() function responsible for key derivation. Due to inconsistent interpretation of return values where OpenSSL uses 0 to indicate failure and libssh uses 0 for success—the function may mistakenly return a success status even when key derivation fails. This results in uninitialized cryptographic key buffers being used in subsequent communication, potentially compromising SSH sessions' confidentiality, integrity, and availability.
Отчет
The Red Hat Product Security team has assessed the severity of this vulnerability as Moderate due to the combination of limited prerequisites and its impact on confidentiality, integrity, and availability. The vulnerability is only present when libssh is built with OpenSSL versions older than 3.0. Successful exploitation could allow an attacker to initiate cryptographic operations using uninitialized keys, which may compromise secure SSH sessions.
Меры по смягчению последствий
To mitigate this issue, administrators should ensure that libssh is built against OpenSSL version 3.0 or later. This change eliminates the return code mismatch and prevents the erroneous use of uninitialized key material. It is also strongly recommended to apply vendor supplied patches or update to the latest libssh security release as soon as possible.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | libssh | Not affected | ||
| Red Hat Enterprise Linux 6 | libssh2 | Out of support scope | ||
| Red Hat Enterprise Linux 7 | libssh2 | Out of support scope | ||
| Red Hat Enterprise Linux 9 | libssh | Affected | ||
| Red Hat OpenShift Container Platform 4 | rhcos | Affected | ||
| Red Hat Enterprise Linux 8 | libssh | Fixed | RHSA-2025:21977 | 24.11.2025 |
| Red Hat Enterprise Linux 8 | libssh | Fixed | RHSA-2025:21977 | 24.11.2025 |
| Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | libssh | Fixed | RHSA-2026:24349 | 08.06.2026 |
| Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | libssh | Fixed | RHSA-2026:24349 | 08.06.2026 |
| Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | libssh | Fixed | RHSA-2026:25911 | 15.06.2026 |
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Дополнительная информация
Статус:
EPSS
5 Medium
CVSS3
Связанные уязвимости
A flaw was found in libssh versions built with OpenSSL versions older than 3.0, specifically in the ssh_kdf() function responsible for key derivation. Due to inconsistent interpretation of return values where OpenSSL uses 0 to indicate failure and libssh uses 0 for success—the function may mistakenly return a success status even when key derivation fails. This results in uninitialized cryptographic key buffers being used in subsequent communication, potentially compromising SSH sessions' confidentiality, integrity, and availability.
A flaw was found in libssh versions built with OpenSSL versions older than 3.0, specifically in the ssh_kdf() function responsible for key derivation. Due to inconsistent interpretation of return values where OpenSSL uses 0 to indicate failure and libssh uses 0 for success—the function may mistakenly return a success status even when key derivation fails. This results in uninitialized cryptographic key buffers being used in subsequent communication, potentially compromising SSH sessions' confidentiality, integrity, and availability.
Libssh: incorrect return code handling in ssh_kdf() in libssh
A flaw was found in libssh versions built with OpenSSL versions older ...
EPSS
5 Medium
CVSS3