CVE-2026-90994 Sssd: sssd: denial of service via malformed pam v1 requests

Description

A flaw was found in sssd, specifically within the PAM (Pluggable Authentication Modules) responder's protocol v1 parser, pam_parse_in_data(). A local client with access to the PAM responder's UNIX socket can exploit this by negotiating protocol v1 and sending an empty or truncated PAM request body. This can trigger an out-of-bounds read, potentially causing the PAM responder to terminate or restart, leading to a local denial of service.

Exploitable with local access to the machine, without an account and without any user action; the impact on data or service is limited.

Attack vector

Local

Attack complexity

Low

Privileges required

None

Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

Low

Affected products and versions