---
id: CVE-2026-104034
title: A flaw was found in SSSD
summary: >-
  A flaw was found in SSSD. A use-after-free vulnerability exists in the
  Kerberos Credential Manager (KCM) responder during Kerberos ticket-granting
  ticket (TGT) renewal, where a deferred callback accesses memory that has
  already been rele…
severity: medium
cvss: 4.7
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-825
vendor: Red Hat
product: sssd
affected:
  - sssd (all versions)
  - sssd
  - sssd (all versions)
  - sssd (all versions)
  - sssd (all versions)
  - openshift/ose-rhel-coreos-8 (all versions)
  - openshift/ose-rhel-coreos-9 (all versions)
published: '2026-10-06'
updated: '2026-10-06'
sourceUpdated: '2026-10-06T15:17:11.980'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-104034'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2026-104034'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2479178'
    label: secalert@redhat.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-104034.json
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-104034'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-104034'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-06T14:42:49.745426Z'
ingestedAt: '2026-10-06T00:37:36.248Z'
epss: 0.00089
epssPercentile: 0.00377
---

## Overview

A flaw was found in SSSD. A use-after-free vulnerability exists in the Kerberos Credential Manager (KCM) responder during Kerberos ticket-granting ticket (TGT) renewal, where a deferred callback accesses memory that has already been released. An authenticated local user with a renewable Kerberos ticket can trigger this issue on systems configured with KCM renewal, causing the KCM responder service to crash and resulting in a Denial of Service (DoS).

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: 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 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-10-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-104034.json)