SSSD PAM responder NULL ptr deref via malformed OAuth2 JSON
CVE-2026-127100 Published on November 12, 2026
Sssd: sssd: local denial of service through unchecked oauth2 json code type in pam responder
A flaw was found in SSSD's PAM responder on builds with the JSON PAM extension enabled. A local attacker can submit a crafted authentication request containing a non-string OAuth2 code value. Missing JSON type validation leads to a NULL pointer dereference, terminating the PAM responder and disrupting SSSD-backed authentication.
Vulnerability Analysis
CVE-2026-127100 is exploitable with local system access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Timeline
Reported to Red Hat.
Made public. 28 days later.
Weakness Type
NULL Pointer Dereference
A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. NULL pointer dereference issues can occur through a number of flaws, including race conditions, and simple programming omissions.
Products Associated with CVE-2026-127100
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Affected Versions
Red Hat Enterprise Linux 10: Red Hat Enterprise Linux 6: Red Hat Enterprise Linux 7: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 9: Red Hat OpenShift Container Platform 4: Red Hat OpenShift Container Platform 4: Red Hat OpenShift Container Platform 5:Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.