CVE-2026-104039 (CVSS 4.7)

Description

A flaw was found in SSSD. A local user can cause a denial of service (DoS) by disrupting system authentication services. When handling Generic Security Services Application Programming Interface (GSSAPI) authentication in the Pluggable Authentication Module (PAM) responder, cached connection state is freed upon completion without clearing the reference pointer. An attacker can exploit this by sending an additional request over the same connection, causing the service to access invalid memory and unexpectedly terminate.

Is your site exposed to CVE-2026-104039?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

4.7

MEDIUM

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0010

Probability of exploitation

0.01%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-825 CWE-825

References

Other References

https://access.redhat.com/security/cve/CVE-2026-104039 https://bugzilla.redhat.com/show_bug.cgi?id=2478956

Frequently Asked Questions

What is CVE-2026-104039? +

A flaw was found in SSSD. A local user can cause a denial of service (DoS) by disrupting system authentication services. When handling Generic Security Services Application Programming Interface (GSSAPI) authentication in the Pluggable Authentication Module (PAM) responder, cached connection state is freed upon completion without clearing the reference pointer. An attacker can exploit this by sending an additional request over the same connection, causing the service to access invalid memory and unexpectedly terminate. It has a CVSS v3.1 base score of 4.7 (MEDIUM).

How severe is CVE-2026-104039? +

CVE-2026-104039 has a CVSS v3.1 score of 4.7 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0010, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-104039? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-53918

odhcpd is the DHCPv6, DHCPv4, and router-advertisement server used by OpenWrt. Prior to version 25.12, odhcpd's DHCPv6 IA handler keeps …

CVE-2026-62929

Expired pointer dereference in the MigTD's virtio-vsock implementation for the Intel(R) TDX Migration Trust Domain (MigTD) within Ring 0: Hypervisor …

CVE-2026-52924 9.8

In the Linux kernel, the following vulnerability has been resolved: sctp: purge outqueue on stale COOKIE-ECHO handling sctp_stream_update() is only …

CVE-2026-53006 9.8

In the Linux kernel, the following vulnerability has been resolved: ipv6: fix possible UAF in icmpv6_rcv() Caching saddr and daddr …

CVE-2024-23310 9.8

A use-after-free vulnerability exists in the sopen_FAMOS_read functionality of The Biosig Project libbiosig 2.5.0 and Master Branch (ab0ee111). A specially …

CVE-2025-49794 9.1

A use-after-free vulnerability was found in libxml2. This issue occurs when parsing XPath elements under certain circumstances when the XML …