# CVE-2021-3634: libssh: libssh is a library which implements the SSH protocol

CVE-2021-3634 is fixed in 5 products on 1 platform, first by libssh-4 0.9.3-2ubuntu2.2, released August 25, 2021. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2021-3634
- Priority: Routine
- CVSS: 6.5 (Low)
- EPSS: 0.0468
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 25, 2021

## Description

libssh is a library which implements the SSH protocol. It can be used to implement client and server applications.  The following packages have been upgraded to a later upstream version: libssh (0.9.6). (BZ#1896651)  Security Fix(es):  * libssh: possible heap-based buffer overflow when rekeying (CVE-2021-3634)  For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.  Additional Changes:  For detailed information on changes in this release, see the Red Hat Enterprise Linux 8.6 Release Notes linked from the References section.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libssh RHEL 8 | 0:0.9.6-3.el8 | [RHSA-2022:2031](https://patchblox.com/security/data/fix/linux/rhsa-2022-2031.md) | May 10, 2022 |
| Linux | libssh almalinux 8 | 0.9.6-3.el8 | [ALSA-2022:2031](https://patchblox.com/security/data/fix/linux/alsa-2022-2031.md) | May 10, 2022 |
| Linux | libssh ol 8 | 0:0.9.6-3.el8 | [ELSA-2022-2031](https://patchblox.com/security/data/fix/linux/elsa-2022-2031.md) | May 17, 2022 |
| Linux | libssh rocky 8 | 0:0.9.6-3.el8 | [RLSA-2022:2031](https://patchblox.com/security/data/fix/linux/rlsa-2022-2031.md) | May 10, 2022 |
| Linux | libssh-4 Ubuntu 20.04 LTS (focal) | 0.9.3-2ubuntu2.2 | [libssh-4 0.9.3-2ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libssh-4-0.9.3-2ubuntu2.2.md) | Aug 25, 2021 |
| Linux | libssh-4 Ubuntu 22.04.1 LTS (jammy) | 0.9.6-1 | [libssh-4 0.9.6-1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libssh-4-0.9.6-1.md) | Aug 25, 2021 |
| Linux | libssh-config RHEL 8 | 0:0.9.6-3.el8 | [RHSA-2022:2031](https://patchblox.com/security/data/fix/linux/rhsa-2022-2031.md) | May 10, 2022 |
| Linux | libssh-config almalinux 8 | 0.9.6-3.el8 | [ALSA-2022:2031](https://patchblox.com/security/data/fix/linux/alsa-2022-2031.md) | May 10, 2022 |
| Linux | libssh-config ol 8 | 0:0.9.6-3.el8 | [ELSA-2022-2031](https://patchblox.com/security/data/fix/linux/elsa-2022-2031.md) | May 17, 2022 |
| Linux | libssh-devel RHEL 8 | 0:0.9.6-3.el8 | [RHSA-2022:2031](https://patchblox.com/security/data/fix/linux/rhsa-2022-2031.md) | May 10, 2022 |
| Linux | libssh-devel almalinux 8 | 0.9.6-3.el8 | [ALSA-2022:2031](https://patchblox.com/security/data/fix/linux/alsa-2022-2031.md) | May 10, 2022 |
| Linux | libssh-devel ol 8 | 0:0.9.6-3.el8 | [ELSA-2022-2031](https://patchblox.com/security/data/fix/linux/elsa-2022-2031.md) | May 17, 2022 |
| Linux | libssh-gcrypt-4 Ubuntu 20.04 LTS (focal) | 0.9.3-2ubuntu2.2 | [libssh-gcrypt-4 0.9.3-2ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libssh-gcrypt-4-0.9.3-2ubuntu2.2.md) | Aug 25, 2021 |
| Linux | libssh-gcrypt-4 Ubuntu 22.04.1 LTS (jammy) | 0.9.6-1 | [libssh-gcrypt-4 0.9.6-1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libssh-gcrypt-4-0.9.6-1.md) | Aug 25, 2021 |

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