How severe is CVE-2026-104039?

CVE-2026-104039 has a CVSS 3.x base score of 4.7, rated medium severity. It is exploitable over local access with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-104039 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (1st percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-104039?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2026-104039 published?

CVE-2026-104039 was published on 2026-10-06.

CVE-2026-104039

CVE-2026-104039 is a medium-severity vulnerability with a CVSS 3.x base score of 4.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-825.

Key facts

Severity: Medium (CVSS 3.x base score 4.7)
EPSS exploit prediction: 0% (1st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-825
Published: 2026-10-06
Last modified: 2026-10-06

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.

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.
How severe is CVE-2026-104039?: CVE-2026-104039 has a CVSS 3.x base score of 4.7, rated medium severity. It is exploitable over local access with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-104039 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (1st percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-104039?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-104039 published?: CVE-2026-104039 was published on 2026-10-06.

References

Other CWE-825 vulnerabilities

CVE-2025-49794 — Critical (CVSS 9.1): A use-after-free vulnerability was found in libxml2. This issue occurs when parsing XPath elements under certain…
CVE-2026-46176 — High (CVSS 7.8): In the Linux kernel, the following vulnerability has been resolved: RDMA/mlx5: Fix error path fall-through in…
CVE-2026-34001 — High (CVSS 7.8): A flaw was found in the X.Org X server. This use-after-free vulnerability occurs in the XSYNC fence triggering logic,…
CVE-2026-8854 — High (CVSS 7.5): IBM HTTP Server 8.5, and 9.0 is vulnerable to denial of service via the optional module mod_mem_cache.
CVE-2025-49795 — High (CVSS 7.5): A NULL pointer dereference vulnerability was found in libxml2 when processing XPath XML expressions. This flaw allows…
CVE-2023-20212 — High (CVSS 7.5): A vulnerability in the AutoIt module of ClamAV could allow an unauthenticated, remote attacker to cause a denial of…

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