# CVE-2026-58050: libssh2 - Integer Overflow in publickey Subsystem Attribute Allocation

CVE-2026-58050 is fixed in 8 products on 1 platform, first by DEBIAN-CVE-2026-58050, released June 28, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-58050
- Priority: High
- CVSS: 7.5 (Important)
- EPSS: 0.0044
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 27, 2026
- Weakness: Integer Overflow or Wraparound
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-58050

## Description

libssh2 through 1.11.1 reads an attacker-controlled 32-bit attribute count from a publickey-subsystem response and uses it in the allocation num_attrs * sizeof(libssh2_publickey_attribute) without bounds checking, so on 32-bit platforms the multiplication overflows to an undersized buffer. A malicious SSH server can then drive the attribute-parsing loop to write past the allocation, causing a heap buffer overflow in a connecting libssh2 client.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libssh2 Debian 12.15 (bookworm) | 1.10.0-3+deb12u1 | [DEBIAN-CVE-2026-58050](https://patchblox.com/security/data/fix/linux/debian-cve-2026-58050.md) | Jun 28, 2026 |
| Linux | libssh2 Debian 13.5 (trixie) | 1.11.1-1+deb13u2 | [DEBIAN-CVE-2026-58050](https://patchblox.com/security/data/fix/linux/debian-cve-2026-58050.md) | Jun 28, 2026 |
| Linux | libssh2 Debian 14 | 1.11.1-6 | [DEBIAN-CVE-2026-58050](https://patchblox.com/security/data/fix/linux/debian-cve-2026-58050.md) | Jun 28, 2026 |
| Linux | libssh2 amzn 2023 | 1.10.0-1.amzn2023.0.5 | [ALAS2023-2026-1966](https://patchblox.com/security/data/fix/linux/alas2023-2026-1966.md) | Jul 20, 2026 |
| Linux | libssh2-1 Ubuntu 18.04.6 LTS (bionic) | 1.8.0-1ubuntu0.1+esm1 | [libssh2-1 1.8.0-1ubuntu0.1+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libssh2-1-1.8.0-1ubuntu0.1-esm1.md) | Jul 24, 2026 |
| Linux | libssh2-1 Ubuntu 20.04 LTS (focal) | 1.8.0-2.1ubuntu0.1+esm1 | [libssh2-1 1.8.0-2.1ubuntu0.1+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libssh2-1-1.8.0-2.1ubuntu0.1-esm1.md) | Jul 24, 2026 |
| Linux | libssh2-1 Ubuntu 22.04.1 LTS (jammy) | 1.10.0-3ubuntu0.1 | [libssh2-1 1.10.0-3ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libssh2-1-1.10.0-3ubuntu0.1.md) | Jul 24, 2026 |
| Linux | libssh2-1t64 Ubuntu 24.04.5 LTS (noble) | 1.11.0-4.1ubuntu0.24.04.3 | [libssh2-1t64 1.11.0-4.1ubuntu0.24.04.3](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libssh2-1t64-1.11.0-4.1ubuntu0.24.04.3.md) | Jul 14, 2026 |
| Linux | libssh2-1t64 Ubuntu 26.04.1 LTS (resolute) | 1.11.1-1ubuntu0.26.04.3 | [libssh2-1t64 1.11.1-1ubuntu0.26.04.3](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libssh2-1t64-1.11.1-1ubuntu0.26.04.3.md) | Jul 24, 2026 |
| Linux | libssh2-debuginfo amzn 2023 | 1.10.0-1.amzn2023.0.5 | [ALAS2023-2026-1966](https://patchblox.com/security/data/fix/linux/alas2023-2026-1966.md) | Jul 20, 2026 |
| Linux | libssh2-debugsource amzn 2023 | 1.10.0-1.amzn2023.0.5 | [ALAS2023-2026-1966](https://patchblox.com/security/data/fix/linux/alas2023-2026-1966.md) | Jul 20, 2026 |
| Linux | libssh2-devel amzn 2023 | 1.10.0-1.amzn2023.0.5 | [ALAS2023-2026-1966](https://patchblox.com/security/data/fix/linux/alas2023-2026-1966.md) | Jul 20, 2026 |
| Linux | libssh2-docs amzn 2023 | 1.10.0-1.amzn2023.0.5 | [ALAS2023-2026-1966](https://patchblox.com/security/data/fix/linux/alas2023-2026-1966.md) | Jul 20, 2026 |
| Linux | libssh2_org opensuse-leap 16.0 | 1.11.1-160000.5.1 | [OPENSUSE-SU-2026:21549-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21549-1.md) | Aug 10, 2026 |
| Linux | libssh2_org sles 15.6 | 1.11.0-150600.20.6.1 | [SUSE-SU-2026:3541-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3541-1.md) | Aug 10, 2026 |
| Linux | libssh2_org sles 15.7 | 1.11.0-150600.20.6.1 | [SUSE-SU-2026:3541-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3541-1.md) | Aug 10, 2026 |
| Linux | libssh2_org sles 16.0 | 1.11.1-160000.5.1 | [SUSE-SU-2026:23225-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23225-1.md) | Aug 10, 2026 |

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Data as of 2026-11-09T07:25:28Z 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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