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.

Attack Vector Network

Attack Complexity High

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact Low

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

Integrity Impact Low

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
libssh2 libssh2 affected
Version Status Constraints
0 affected ≤ 1.11.1

No data.

No data.

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Project Subscriptions

Vendors Products
Libssh2 Subscribe
Libssh2 Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/bikini/exploitarium/tree/main/libssh2-publickey-list-calc-poc cve-icon
https://github.com/libssh2/libssh2/blob/master/src/publickey.c cve-icon
https://www.vulncheck.com/advisories/libssh2-integer-overflow-in-publickey-subsystem-attribute-allocation cve-icon
History

Sun, 28 Jun 2026 02:15:00 +0000

Type Values Removed Values Added
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.
Title libssh2 - Integer Overflow in publickey Subsystem Attribute Allocation
First Time appeared Libssh2
Libssh2 libssh2
Weaknesses CWE-190
CPEs cpe:2.3:a:libssh2:libssh2:*:*:*:*:*:*:*:*
Vendors & Products Libssh2
Libssh2 libssh2
References
Metrics cvssV3_1

{'score': 7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H'}

cvssV4_0

{'score': 8.3, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-06-28T01:32:53.582Z

Reserved: 2026-06-28T00:55:25.426Z

Link: CVE-2026-58050

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses