CVE-2026-12610
Description
A flaw was found in sssd. When authenticating with a YubiKey, the SSSD PAM responder can crash due to a use-after-free vulnerability, where a memory pointer is incorrectly handled. A local attacker could exploit this flaw by manipulating smartcard or YubiKey contents, leading to a denial of service that disrupts authentication. This vulnerability also presents a potential for privilege escalation, although it is difficult to exploit.
Statement
This Moderate impact use-after-free flaw in the SSSD PAM responder can lead to a denial of service during YubiKey authentication, causing the process to crash and disrupt user access. While there is a theoretical potential for privilege escalation, exploitation is considered difficult due to the specific conditions required, which involve an attacker controlling smartcard contents during an active authentication attempt.
Mitigation
Configure the sssd systemd service to automatically restart on failure. This ensures authentication remains available even if an attacker triggers the denial-of-service crash.
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).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.4 | N/A | 6.4 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | High | N/A | High |
| Privileges Required | High | N/A | High |
| 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:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
If the expired pointer is used in a read operation, an attacker might be able to control data read in by the application.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If the expired pointer references a memory location that is not accessible to the product, or points to a location that is "malformed" (such as NULL) or larger than expected by a read or write operation, then a crash may occur.
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If the expired pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.
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