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A flaw was found in SSSD. A local user can cause a denial of service (DoS) by disrupting system authentication services. (CVE-2026-104039)

0
Medium
VulnerabilityCVE-2026-104039gcveosvubuntu-cve-2026-104039cve-2026-104039ubuntu-pro-16-04-ltsubuntu-pro-18-04-ltsubuntu-pro-20-04-ltsubuntu-22-04-ltsubuntu-24-04-ltsubuntu-26-04-lts
Published: 10/06/2026 (10/06/2026, 02:17:00 UTC)
Source: GCVE Database
Product: sssd

Description

A vulnerability in SSSD allows a local user to cause a denial of service (DoS) by disrupting system authentication services. The flaw occurs in the handling of GSSAPI authentication in the PAM responder, where cached connection state is freed without clearing the reference pointer. This can lead to the service accessing invalid memory and terminating unexpectedly.

CVSS v3.1

Score 4.7medium

Attack Vector
Local
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected software

Ubuntu:Pro:16.04:LTSmore threats →ghsa
sssd
pkg:deb/ubuntu/sssd?arch=source&distro=esm-infra-legacy/xenial
Affected versions
=1.12.5-2=1.13.1-2=1.13.2-1=1.13.3-1=1.13.4-1=1.13.4-1ubuntu1=1.13.4-1ubuntu1.1=1.13.4-1ubuntu1.2=1.13.4-1ubuntu1.5=1.13.4-1ubuntu1.6=1.13.4-1ubuntu1.7=1.13.4-1ubuntu1.8=1.13.4-1ubuntu1.9=1.13.4-1ubuntu1.10=1.13.4-1ubuntu1.11=1.13.4-1ubuntu1.12=1.13.4-1ubuntu1.13=1.13.4-1ubuntu1.14=1.13.4-1ubuntu1.15=1.13.4-1ubuntu1.15+esm1
Ubuntu:Pro:18.04:LTSmore threats →ghsa
sssd
pkg:deb/ubuntu/sssd?arch=source&distro=esm-infra/bionic
Affected versions
=1.15.3-2ubuntu1=1.15.3-3ubuntu1=1.16.0-5ubuntu1=1.16.0-5ubuntu2=1.16.1-1ubuntu1=1.16.1-1ubuntu1.1=1.16.1-1ubuntu1.2=1.16.1-1ubuntu1.3=1.16.1-1ubuntu1.4=1.16.1-1ubuntu1.5=1.16.1-1ubuntu1.6=1.16.1-1ubuntu1.7=1.16.1-1ubuntu1.8=1.16.1-1ubuntu1.8+esm1
Ubuntu:Pro:20.04:LTSmore threats →ghsa
sssd
pkg:deb/ubuntu/sssd?arch=source&distro=esm-infra/focal
Affected versions
=2.2.0-4ubuntu1=2.2.2-1=2.2.2-1ubuntu1=2.2.3-1.1ubuntu1=2.2.3-2=2.2.3-3=2.2.3-3ubuntu0.1=2.2.3-3ubuntu0.2=2.2.3-3ubuntu0.3=2.2.3-3ubuntu0.4=2.2.3-3ubuntu0.6=2.2.3-3ubuntu0.7=2.2.3-3ubuntu0.8=2.2.3-3ubuntu0.9=2.2.3-3ubuntu0.10=2.2.3-3ubuntu0.11=2.2.3-3ubuntu0.12=2.2.3-3ubuntu0.13=2.2.3-3ubuntu0.13+esm1
Ubuntu:22.04:LTSmore threats →ghsa
sssd
pkg:deb/ubuntu/sssd?arch=source&distro=jammy
Affected versions
=2.4.1-2ubuntu4=2.5.2-4ubuntu1=2.5.2-4ubuntu3=2.5.2-4ubuntu4=2.6.1-1ubuntu3=2.6.3-1ubuntu3=2.6.3-1ubuntu3.1=2.6.3-1ubuntu3.2=2.6.3-1ubuntu3.3=2.6.3-1ubuntu3.4=2.6.3-1ubuntu3.5=2.6.3-1ubuntu3.6=2.6.3-1ubuntu3.8=2.6.3-1ubuntu3.9
Ubuntu:24.04:LTSmore threats →ghsa
sssd
pkg:deb/ubuntu/sssd?arch=source&distro=noble
Affected versions
=2.9.1-2ubuntu2=2.9.1-2ubuntu3=2.9.2-1ubuntu2=2.9.4-1ubuntu1=2.9.4-1.1ubuntu3=2.9.4-1.1ubuntu5=2.9.4-1.1ubuntu6=2.9.4-1.1ubuntu6.1=2.9.4-1.1ubuntu6.2=2.9.4-1.1ubuntu6.3=2.9.4-1.1ubuntu6.4=2.9.4-1.1ubuntu6.5=2.9.4-1.1ubuntu6.6=2.9.4-1.1ubuntu6.7=2.9.4-1.1ubuntu6.8
Ubuntu:26.04:LTSmore threats →ghsa
sssd
pkg:deb/ubuntu/sssd?arch=source&distro=resolute
Affected versions
=2.10.1-2ubuntu5=2.10.1-2ubuntu7=2.12.0-1ubuntu3=2.12.0-1ubuntu4=2.12.0-1ubuntu5=2.12.0-1ubuntu5.1=2.12.0-1ubuntu5.2=2.12.0-1ubuntu5.3=2.12.0-1ubuntu5.4=2.12.0-1ubuntu5.5

Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.

AI-Powered Analysis

Machine-generated threat intelligence

AILast updated: 10/08/2026, 22:16:15 UTC

Technical Analysis

CVE-2026-104039 is a local denial of service vulnerability in SSSD related to the handling of Generic Security Services Application Programming Interface (GSSAPI) authentication within the Pluggable Authentication Module (PAM) responder. Specifically, after completion of a request, the cached connection state is freed but the reference pointer is not cleared. An attacker can exploit this by sending an additional request over the same connection, causing the service to access invalid memory and crash, disrupting system authentication services.

Potential Impact

The vulnerability allows a local attacker to cause a denial of service by crashing the SSSD service, which disrupts system authentication. There is no impact on confidentiality or integrity, only availability is affected.

Mitigation Recommendations

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict local user access to trusted users only to reduce risk.

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Technical Details

Gcve Source
db.gcve.eu
Osv Id
UBUNTU-CVE-2026-104039
Osv Schema Version
1.7.0
Ecosystems
["Ubuntu:Pro:16.04:LTS","Ubuntu:Pro:18.04:LTS","Ubuntu:Pro:20.04:LTS","Ubuntu:22.04:LTS","Ubuntu:24.04:LTS","Ubuntu:26.04:LTS"]
Cvss Version
3.1
State
PUBLISHED

Threat ID: 6ac80fcb2cdf04f65639c4b8

Added to database: 10/08/2026, 21:48:59 UTC

Last enriched: 10/08/2026, 22:16:15 UTC

Last updated: 10/09/2026, 04:48:07 UTC

Views: 3

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