CVE-2026-104034: Sssd: sssd: denial of service via use-after-free in kcm ticket renewal
- Is it exploited?
Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of . If CISA adds it, this page shows it as known exploited.
- How likely is exploitation in the next 30 days?
- <0.1%
EPSS score, percentile 0.4 of all scored records. A probability estimated by FIRST, not a report of exploitation.
- How severe?
- 4.7 Medium
CVSS v3.1 base score, given by the CNA
- What should I do?
CISA has set no required action, because the vulnerability is not in KEV.
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Source: CISA KEV 2026.10.29, as of ; FIRST EPSS, as of ; CVE List, as of . About the data.
What to do
Workaround (from the CVE record)
KCM ticket renewal, the affected feature, is disabled by default (tgt_renewal defaults to false). On systems where it has been enabled, it can be disabled to avoid the vulnerable code path: 1. Edit /etc/sssd/sssd.conf and set `tgt_renewal = false` in the `[kcm]` section. 2. Restart the SSSD KCM responder to apply the change: systemctl restart sssd-kcm.service Note: disabling TGT renewal means renewable Kerberos tickets stored in the KCM credential cache are no longer renewed automatically and must be re-acquired (for example, with kinit) before they expire. Restarting sssd-kcm.service briefly interrupts in-flight KCM requests.
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
This summary is based on the CVE record as of . Check the vendor's advisory before you act: affected versions and fixes can change.
Affected products and versions
As listed in the CVE record.
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Versions not listed are: unknown.
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Versions not listed are: affected.
Source: CVE List, as of . About the data.
About this vulnerability
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 servic…
Summary: CVE record, as of .
- CISA has not added CVE-2026-104034 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
- The CVE record was published on 6 Oct 2026.
- The CVE record carries a CVSS v3.1 base score of 4.7 (Medium), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at <0.1% (percentile 0.4), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
- CISA's SSVC assessment in the CVE record: exploitation none, automatable no, technical impact partial.
- The credits in the CVE record name AISLE as finder.
Source: CISA KEV 2026.10.29, as of ; CVE List, as of ; FIRST EPSS, as of . About the data.
Description
Sssd: sssd: denial of service via use-after-free in kcm ticket renewal
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).
Source: CVE List, as of . About the data.
Weakness
CWE-825
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record.
Timeline
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References
2
Known exploited Red Hat vulnerabilities
- CVE-2015-3246: Red Hat Libuser Race Condition Vulnerability
- CVE-2015-5287: Red Hat Automatic Bug Reporting Tool Privilege Escalation Vulnerability
- CVE-2018-14667: Red Hat JBoss RichFaces Framework Expression Language Injection Vulnerability
- CVE-2021-3560: Red Hat Polkit Incorrect Authorization Vulnerability
- CVE-2021-4034: Red Hat Polkit Out-of-Bounds Read and Write Vulnerability