Medium

CVE-2026-104039 — Sssd: sssd: denial of service via stale connection state reuse in pam gssapi responder

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.

Published Oct 5, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: redhat

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.1% (30-day exploitation probability)+0
Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.1%

ahead of 1% of scored CVEs · Oct 15, 2026

Affects

Red Hat

Red Hat Enterprise Linux 10 and 4 more

CVSS base

4.7

Medium · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Red Hat Red Hat Enterprise Linux 10, Red Hat Red Hat Enterprise Linux 7, Red Hat Red Hat Enterprise Linux 8…).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Red Hat	Red Hat Enterprise Linux 10	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP
Red Hat	Red Hat Enterprise Linux 7	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP
Red Hat	Red Hat Enterprise Linux 8	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP
Red Hat	Red Hat Enterprise Linux 9	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP
Red Hat	Red Hat OpenShift Container Platform 4	versions not specified by the source	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Local

Attack complexity

High

Privileges required

Low

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
4.7	CVSS 3.1	Medium	1.0	3.6	secalert@redhat.com via NIST National Vulnerability Database
4.7	CVSS 3.1	Medium	—	—	redhat via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H (score shown at the top: secalert@redhat.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-825

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 0.10%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.

endpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

2026
Affected products added · red hat/red hat enterprise linux 10, red hat/red hat enterprise linux 7, red hat/red hat enterprise linux 8, red hat/red
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
CVSS changed · 4.7
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Undergoing Analysis
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
Oct 5, 2026 · redhat

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

2 on the record

bugzilla.redhat.com/show_bug.cgi
issue-tracking, x_refsource_REDHAT, NIST National Vulnerability Database
access.redhat.com/security/cve/CVE-2026-104039
vdb-entry, x_refsource_REDHAT, NIST National Vulnerability Database

Elsewhere on this site

Red Hat
every CVE for this vendor

CWE-825
other pages naming this weakness

Related CVEs (same products)

Low CVE-2026-111581 Libblockdev: libblockdev: argument injection in ntfs/vfat label-setting helpers via udisks2 setlabel() d-bus method 1h
Medium CVE-2026-111555 Luksmeta: missing slot-range validation permits out-of-gap device i/o 4h
High CVE-2026-105958 Spice-server: spice: heap oob read/write via unchecked migration data offsets 4h
High CVE-2026-105959 Spice-server: spice: heap buffer overflow via glz dictionary max_encoders integer truncation 5h
High CVE-2026-104715 Cifs-utils: mount.cifs credential-file option injection allows local privilege boundary bypass 10h
High CVE-2026-92982 Ansible-operator-plugins: ansible operator plugins: arbitrary code execution via jinja2 template injection 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No fixed version, patch or mitigation documented.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-104039 is "Sssd: sssd: denial of service via stale connection state reuse in pam gssapi responder", rated Medium. It affects Red Hat Enterprise Linux 10 (Red Hat); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 4.7 describes technical severity. EPSS 0.10% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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