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PatchSiren cyber security CVE debrief

CVE-2026-90994 Red Hat CVE debrief

A local denial-of-service vulnerability was found in the sssd PAM responder's protocol v1 parser. 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, potentially causing the PAM responder to terminate or restart. This issue arises from an out-of-bounds read triggered by malformed PAM requests. System administrators should assess exposure and consider patches or mitigations to prevent service disruption.

Vendor
Red Hat
Product
Red Hat Enterprise Linux 10
CVSS
MEDIUM 4
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-14
Original CVE updated
2026-10-16
Advisory published
2026-09-14
Advisory updated
2026-10-16

Who should care

System administrators and security teams responsible for sssd installations, particularly those with local clients accessing the PAM responder's UNIX socket, should assess exposure and consider applying patches or mitigations.

Why it matters

This vulnerability allows a local client to cause a denial of service in the sssd PAM responder. System administrators and security teams should assess exposure and consider applying patches or mitigations to prevent potential service disruption.

  • Potential termination or restart of the PAM responder
  • Local denial of service impacting system availability

Technical summary

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.

Defensive priority

Medium priority for systems administrators and security teams to assess exposure and apply patches or mitigations.

Recommended defensive actions

  • Assess exposure of sssd installations to this vulnerability
  • Verify if local clients have access to the PAM responder's UNIX socket
  • Consider applying patches or mitigations provided by the vendor
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and source item provide details on the vulnerability, but specific version information and remediation steps are not provided. Further investigation is required to determine affected versions and apply patches or mitigations.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-90994 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-90994

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-90994 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-90994

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.