# CVE-2026-59842: libssh: A flaw was found in libssh

CVE-2026-59842 is fixed in 3 products on 1 platform, first by DEBIAN-CVE-2026-59842, released July 31, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-59842
- Priority: High
- CVSS: 8.8 (medium)
- EPSS: 0.0049
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 21, 2026

## Description

A flaw was found in libssh. During server-side GSSAPI key exchange, a client-supplied Curve25519 public key shorter than the expected length is copied without proper length validation, leading to an out-of-bounds heap read. This could allow a remote unauthenticated attacker to disclose small amounts of server memory.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libssh Debian 14 | 0.12.1-1 | [DEBIAN-CVE-2026-59842](https://patchblox.com/security/data/fix/linux/debian-cve-2026-59842.md) | Jul 31, 2026 |
| Linux | libssh RHEL 10 | 0.12.0-3.el10_2 | [RHSA-2026:55855](https://patchblox.com/security/data/fix/linux/rhsa-2026-55855.md) | Aug 18, 2026 |
| Linux | libssh almalinux 10 | 0.12.0-3.el10_2 | [ALSA-2026:55855](https://patchblox.com/security/data/fix/linux/alsa-2026-55855.md) | Aug 17, 2026 |
| Linux | libssh ol 10 | 0:0.12.0-3.el10_2 | [ELSA-2026-55855](https://patchblox.com/security/data/fix/linux/elsa-2026-55855.md) | Aug 17, 2026 |
| Linux | libssh rocky 10 | 0:0.12.0-3.el10_2 | [RLSA-2026:55855](https://patchblox.com/security/data/fix/linux/rlsa-2026-55855.md) | Aug 18, 2026 |
| Linux | libssh-config almalinux 10 | 0.12.0-3.el10_2 | [ALSA-2026:55855](https://patchblox.com/security/data/fix/linux/alsa-2026-55855.md) | Aug 17, 2026 |
| Linux | libssh-config ol 10 | 0:0.12.0-3.el10_2 | [ELSA-2026-55855](https://patchblox.com/security/data/fix/linux/elsa-2026-55855.md) | Aug 17, 2026 |
| Linux | libssh-devel almalinux 10 | 0.12.0-3.el10_2 | [ALSA-2026:55855](https://patchblox.com/security/data/fix/linux/alsa-2026-55855.md) | Aug 17, 2026 |
| Linux | libssh-devel ol 10 | 0:0.12.0-3.el10_2 | [ELSA-2026-55855](https://patchblox.com/security/data/fix/linux/elsa-2026-55855.md) | Aug 17, 2026 |

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Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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