CVE-2026-7598
Description
A flaw was found in the libssh2 library. A remote attacker can exploit an integer overflow vulnerability in the userauth_password function by manipulating the username_len or password_len arguments and cause a heap-based buffer overflow. This leads to a crash to the application linked to the library and potentially allows arbitrary code execution.
Statement
To exploit this flaw, an attacker needs to be able to supply an excessively large value to the arguments of the userauth_password function, typically to an application processing untrusted SSH authentication requests. The primary security impact of this issue is a crash to the application linked to the library due to memory corruption, potentially allowing arbitrary code execution.
Default Red Hat Enterprise Linux security features, including SELinux enforcement, Address Space Layout Randomization (ASLR) and NX (No-Execute) stack protection, significantly increase the difficulty of achieving arbitrary code execution, limiting the impact of this vulnerability.
Due to these reasons, this vulnerability has been rated with an important severity.
Mitigation
To mitigate this flaw, applications linked to the libssh2 library should be configured or updated to exclusively use public key authentication. Explicitly disabling password-based logins prevents the application from executing the vulnerable userauth_password function.
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 | 9.1 | N/A | 9.1 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
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