CVE-2026-58050

Publication date 28 June 2026

Last updated 7 July 2026

Ubuntu priority

Cvss 3 Severity Score

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.

Status

Show unmaintained releases

Package	Ubuntu Release	Status
libssh2	26.04 LTS resolute	Needs evaluation
	25.10 questing	Needs evaluation
	24.04 LTS noble	Needs evaluation
	22.04 LTS jammy	Needs evaluation
	20.04 LTS focal	Needs evaluation
	18.04 LTS bionic	Needs evaluation
	14.04 LTS trusty	Needs evaluation

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
libssh2	Upstream: 7c8a170

Severity score breakdown

CVSS version:

Base score 8.3 · High

Base metrics

Parameter	Value
Attack vector	Network
Attack complexity	High
Attack requirements	None
Privileges required	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

Scores

Parameter	Value
Base score	8.3 · High
Base + Threat score	-
Base + Environmental score	-
Base + Threat + Environmental score	-

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

Base score 7.0 · High

Base metrics

Parameter	Value
Attack vector	Network
Attack complexity	High
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality impact	Low
Integrity impact	Low
Availability impact	High

Scores

Parameter	Value
Base score	7.0 · High
Exploitability score	-
Impact score	-

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H