A flaw was found in libssh's handling of key exchange (KEX) processes when a client repeatedly sends incorrect KEX guesses. The library fails to free memory during these rekey operations, which can gradually exhaust system memory. This issue can lead to crashes on the client side, particularly when using libgcrypt, which impacts application stability and availability.
CVSS Details
- CVSS 3.1 Base Score: 3.1
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alma_linux | — | Upgrade libssh-develUpgrade libssh-configUpgrade libssh | May 27, 2026 | May 19, 2026 |
| Amazon_linux_2023 | — | Upgrade libssh-configUpgrade libssh-develUpgrade libssh-debuginfoUpgrade libssh-debugsourceUpgrade libssh | Nov 11, 2025 | Sep 9, 2025 |
| Debian | — | Upgrade libssh | Nov 28, 2025 | Nov 28, 2025 |
| Huawei Euleros 2_0_sp10 | — | Upgrade libssh | Jan 15, 2026 | Jan 13, 2026 |
| Huawei Euleros 2_0_sp11 | — | Upgrade libssh | Dec 12, 2025 | Dec 11, 2025 |
| Huawei Euleros 2_0_sp12 | — | Upgrade libssh | Jan 15, 2026 | Jan 13, 2026 |
| Huawei Euleros 2_0_sp13 | — | Upgrade libssh | Dec 12, 2025 | Dec 11, 2025 |
| Redhat_linux | — | No solution existsUpgrade libssh-develUpgrade libssh-configUpgrade libsshUpgrade libssh-debuginfoUpgrade libssh-debugsource | May 20, 2026 | Sep 9, 2025 |
| Rocky_linux | — | Upgrade libssh-develUpgrade libsshUpgrade libssh-debugsourceUpgrade libssh-debuginfo | Jun 1, 2026 | May 28, 2026 |
| Suse | — | Upgrade libssh-develUpgrade libssh-devel-docUpgrade libssh4Upgrade libssh4-32bitUpgrade libssh-config | Dec 5, 2025 | Sep 26, 2025 |
| Ubuntu | — | Upgrade libssh-4Upgrade libssh-4 (Ubuntu Pro) | Feb 19, 2026 | Sep 9, 2025 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Jun 29, 2026 | Sep 9, 2025 |
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