CVE-2026-39828
Description
A flaw was found in golang.org/x/crypto/ssh. A remote attacker could exploit this vulnerability when an SSH server authentication callback returned a PartialSuccessError with non-nil permissions. This flaw caused these permissions to be silently discarded, potentially bypassing certificate restrictions, such as a force-command, after a second authentication factor succeeded. This could lead to unauthorized command execution or access.
Statement
This is an Important security flaw in the golang.org/x/crypto/ssh library. When an SSH server utilizing this library is configured with specific authentication callbacks that return a PartialSuccessError with non-nil permissions, an attacker could bypass intended certificate restrictions, such as force-command. This bypass could lead to unauthorized command execution or access on affected Red Hat systems configured with multi-factor authentication and certificate-based access controls.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.8 | N/A | 8.8 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Confidentiality,Integrity
Technical Impact: Read Application Data; Modify Application Data
Frequently Asked Questions
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