# CVE-2026-59844: Libssh: libssh: denial of service via oversized sftp read length

CVE-2026-59844 is fixed in 6 products on 1 platform, first by libssh-4 0.11.3-1ubuntu2.1, released July 21, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-59844
- Priority: High
- CVSS: 8.8 (Moderate)
- EPSS: 0.0057
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 21, 2026
- Weakness: Memory Allocation with Excessive Size Value
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-59844

## Description

A flaw was found in libssh. A remote authenticated client can issue SSH_FXP_READ requests with an arbitrarily large length, causing a libssh SFTP server to allocate excessive memory and potentially exhaust it through repeated requests.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libssh Debian 12.15 (bookworm) | 0.10.6-0+deb12u3 | [DEBIAN-CVE-2026-59844](https://patchblox.com/security/data/fix/linux/debian-cve-2026-59844.md) | Jul 31, 2026 |
| Linux | libssh Debian 13.5 (trixie) | 0.11.5-0+deb13u1 | [DEBIAN-CVE-2026-59844](https://patchblox.com/security/data/fix/linux/debian-cve-2026-59844.md) | Jul 31, 2026 |
| Linux | libssh Debian 14 | 0.12.1-1 | [DEBIAN-CVE-2026-59844](https://patchblox.com/security/data/fix/linux/debian-cve-2026-59844.md) | Jul 31, 2026 |
| Linux | libssh Fedora 43 | 0.11.5-1.fc43 | [FEDORA-2026-063CAA9112](https://patchblox.com/security/data/fix/linux/fedora-2026-063caa9112.md) | Jul 21, 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 RHEL 8 | 0:0.9.6-17.el8_10 | [RHSA-2026:62218](https://patchblox.com/security/data/fix/linux/rhsa-2026-62218.md) | Sep 13, 2026 |
| Linux | libssh RHEL 9 | 0:0.10.4-19.el9_8 | [RHSA-2026:62217](https://patchblox.com/security/data/fix/linux/rhsa-2026-62217.md) | Sep 13, 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 almalinux 8 | 0.9.6-17.el8_10 | [ALSA-2026:62218](https://patchblox.com/security/data/fix/linux/alsa-2026-62218.md) | Sep 1, 2026 |
| Linux | libssh almalinux 9 | 0.10.4-19.el9_8 | [ALSA-2026:62217](https://patchblox.com/security/data/fix/linux/alsa-2026-62217.md) | Sep 1, 2026 |
| Linux | libssh amzn 2023 | 0.10.6-1.amzn2023.0.9 | [ALAS2023-2026-3096](https://patchblox.com/security/data/fix/linux/alas2023-2026-3096.md) | Sep 28, 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 ol 8 | 0:0.9.6-17.el8_10 | [ELSA-2026-62218-0](https://patchblox.com/security/data/fix/linux/elsa-2026-62218-0.md) | Sep 1, 2026 |
| Linux | libssh ol 9 | 0:0.10.4-19.el9_8 | [ELSA-2026-62217-0](https://patchblox.com/security/data/fix/linux/elsa-2026-62217-0.md) | Sep 1, 2026 |
| Linux | libssh opensuse-leap 16.0 | 0.11.5-160000.1.1 | [OPENSUSE-SU-2026:21444-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21444-1.md) | Jul 25, 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 rocky 8 | 0:0.9.6-17.el8_10 | [RLSA-2026:62218](https://patchblox.com/security/data/fix/linux/rlsa-2026-62218.md) | Sep 2, 2026 |
| Linux | libssh rocky 9 | 0:0.10.4-19.el9_8 | [RLSA-2026:62217](https://patchblox.com/security/data/fix/linux/rlsa-2026-62217.md) | Sep 2, 2026 |
| Linux | libssh sles 15.6 | 0.9.8-150600.11.15.1 | [SUSE-SU-2026:3330-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3330-1.md) | Jul 28, 2026 |
| Linux | libssh sles 15.7 | 0.9.8-150600.11.15.1 | [SUSE-SU-2026:3330-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3330-1.md) | Jul 28, 2026 |
| Linux | libssh sles 16.0 | 0.11.5-160000.1.1 | [SUSE-SU-2026:22956-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22956-1.md) | Jul 25, 2026 |
| Linux | libssh-4 Ubuntu 26.04.1 LTS (resolute) | 0.11.3-1ubuntu2.1 | [libssh-4 0.11.3-1ubuntu2.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libssh-4-0.11.3-1ubuntu2.1.md) | Jul 21, 2026 |
| Linux | libssh-config Fedora 43 | 0.11.5-1.fc43 | [FEDORA-2026-063CAA9112](https://patchblox.com/security/data/fix/linux/fedora-2026-063caa9112.md) | Jul 21, 2026 |
| Linux | libssh-config RHEL 8 | 0:0.9.6-17.el8_10 | [RHSA-2026:62218](https://patchblox.com/security/data/fix/linux/rhsa-2026-62218.md) | Sep 13, 2026 |
| Linux | libssh-config RHEL 9 | 0:0.10.4-19.el9_8 | [RHSA-2026:62217](https://patchblox.com/security/data/fix/linux/rhsa-2026-62217.md) | Sep 13, 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 almalinux 8 | 0.9.6-17.el8_10 | [ALSA-2026:62218](https://patchblox.com/security/data/fix/linux/alsa-2026-62218.md) | Sep 1, 2026 |
| Linux | libssh-config almalinux 9 | 0.10.4-19.el9_8 | [ALSA-2026:62217](https://patchblox.com/security/data/fix/linux/alsa-2026-62217.md) | Sep 1, 2026 |
| Linux | libssh-config amzn 2023 | 0.10.6-1.amzn2023.0.9 | [ALAS2023-2026-3096](https://patchblox.com/security/data/fix/linux/alas2023-2026-3096.md) | Sep 28, 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-config ol 8 | 0:0.9.6-17.el8_10 | [ELSA-2026-62218-0](https://patchblox.com/security/data/fix/linux/elsa-2026-62218-0.md) | Sep 1, 2026 |
| Linux | libssh-config ol 9 | 0:0.10.4-19.el9_8 | [ELSA-2026-62217-0](https://patchblox.com/security/data/fix/linux/elsa-2026-62217-0.md) | Sep 1, 2026 |
| Linux | libssh-debuginfo Fedora 43 | 0.11.5-1.fc43 | [FEDORA-2026-063CAA9112](https://patchblox.com/security/data/fix/linux/fedora-2026-063caa9112.md) | Jul 21, 2026 |
| Linux | libssh-debuginfo amzn 2023 | 0.10.6-1.amzn2023.0.9 | [ALAS2023-2026-3096](https://patchblox.com/security/data/fix/linux/alas2023-2026-3096.md) | Sep 28, 2026 |
| Linux | libssh-debugsource Fedora 43 | 0.11.5-1.fc43 | [FEDORA-2026-063CAA9112](https://patchblox.com/security/data/fix/linux/fedora-2026-063caa9112.md) | Jul 21, 2026 |
| Linux | libssh-debugsource amzn 2023 | 0.10.6-1.amzn2023.0.9 | [ALAS2023-2026-3096](https://patchblox.com/security/data/fix/linux/alas2023-2026-3096.md) | Sep 28, 2026 |
| Linux | libssh-devel Fedora 43 | 0.11.5-1.fc43 | [FEDORA-2026-063CAA9112](https://patchblox.com/security/data/fix/linux/fedora-2026-063caa9112.md) | Jul 21, 2026 |
| Linux | libssh-devel RHEL 8 | 0:0.9.6-17.el8_10 | [RHSA-2026:62218](https://patchblox.com/security/data/fix/linux/rhsa-2026-62218.md) | Sep 13, 2026 |
| Linux | libssh-devel RHEL 9 | 0:0.10.4-19.el9_8 | [RHSA-2026:62217](https://patchblox.com/security/data/fix/linux/rhsa-2026-62217.md) | Sep 13, 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 almalinux 8 | 0.9.6-17.el8_10 | [ALSA-2026:62218](https://patchblox.com/security/data/fix/linux/alsa-2026-62218.md) | Sep 1, 2026 |
| Linux | libssh-devel almalinux 9 | 0.10.4-19.el9_8 | [ALSA-2026:62217](https://patchblox.com/security/data/fix/linux/alsa-2026-62217.md) | Sep 1, 2026 |
| Linux | libssh-devel amzn 2023 | 0.10.6-1.amzn2023.0.9 | [ALAS2023-2026-3096](https://patchblox.com/security/data/fix/linux/alas2023-2026-3096.md) | Sep 28, 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 |
| Linux | libssh-devel ol 8 | 0:0.9.6-17.el8_10 | [ELSA-2026-62218-0](https://patchblox.com/security/data/fix/linux/elsa-2026-62218-0.md) | Sep 1, 2026 |
| Linux | libssh-devel ol 9 | 0:0.10.4-19.el9_8 | [ELSA-2026-62217-0](https://patchblox.com/security/data/fix/linux/elsa-2026-62217-0.md) | Sep 1, 2026 |

---

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