Sources: National Vulnerability Database, CVE.org, CISA KEV, FIRST EPSS
CVE-2026-112321 Overview
The AUTH_GSSAPI handler in lib/rpc/svc_auth_gssapi.c in MIT Kerberos 5 (aka krb5) does not free decoded arguments on certain error paths, which allows remote attackers to cause a denial of service (memory exhaustion in kadmind) via crafted AUTH_GSSAPI_INIT requests that trigger authentication failures.
Critical Impact
Affected Products
- Red Hat AUTH_GSSAPI handler in lib/rpc/svc_auth_gssapi.c in MIT Kerberos: see the vendor advisory for the exact affected versions
Discovery Timeline
- 2026-11-09: CVE-2026-112321 published to the National Vulnerability Database by secalert@redhat.com
- 2026-11-09: last updated in the NVD database
Technical Details for CVE-2026-112321
Vulnerability Analysis
CVE-2026-112321 is a Security Vulnerability weakness (CWE-772) in Red Hat AUTH_GSSAPI handler in lib/rpc/svc_auth_gssapi.c in MIT Kerberos. Based on its CVSS vector, the flaw can be reached over the network, needs no login, and needs no user interaction.
With a CVSS base score of 7.5, apply the vendor fix and confirm exposure on internet facing and business critical assets first.
Root Cause
The vendor description states: The AUTH_GSSAPI handler in lib/rpc/svc_auth_gssapi.c in MIT Kerberos 5 (aka krb5) does not free decoded arguments on certain error paths, which allows remote attackers to cause a denial of service (memory exhaustion in kadmind) via crafted AUTH_GSSAPI_INIT requests that trigger authentication failures.
Attack Vector
Based on the CVSS vector, the flaw can be reached over the network, needs no login, and needs no user interaction. Attack complexity is low complexity.
No exploitation in the wild is confirmed by CISA at the time of the last update. Check the references below for any vendor or researcher proof of concept.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Detection Methods for CVE-2026-112321
Detection Strategies
- Inventory every instance of Red Hat AUTH_GSSAPI handler in lib/rpc/svc_auth_gssapi.c in MIT Kerberos and compare the running version with the affected range above.
- Check external attack surface scans for internet facing instances of the component.
- Run an authenticated vulnerability scan once your scanner ships a check for this CVE.
Monitoring Recommendations
- Forward Red Hat AUTH_GSSAPI handler in lib/rpc/svc_auth_gssapi.c in MIT Kerberos application, access and audit logs to your SIEM for retrospective hunting.
- Alert on new processes, configuration changes or outbound connections from the affected service.
- Track the vendor advisory and the CISA KEV catalog for changes in exploitation status.
How to Mitigate CVE-2026-112321
Immediate Actions Required
- Apply the fixed version of Red Hat AUTH_GSSAPI handler in lib/rpc/svc_auth_gssapi.c in MIT Kerberos named in the vendor advisory.
- Prioritize internet facing and business critical instances first.
- Rescan after the change to confirm the exposure is closed.
Patch Information
Use the fixed version listed in the vendor advisory for Red Hat AUTH_GSSAPI handler in lib/rpc/svc_auth_gssapi.c in MIT Kerberos.
Workarounds
- If patching must wait, restrict network access to the affected service and place it behind authentication or a web application firewall rule.
CWE References
Technical References
This entry is built directly from NVD, CISA KEV and EPSS data. Verify fixed versions in the vendor advisory before you deploy.
Frequently asked questions
Related CVEs
A flaw was found in the deployment-operation family of WildFly Core. Certain handlers, such as upload-deployment-url, lack proper sensitivity classification, allowing an administrator with the restricted "Maintainer" role to read sensitive configuration files. This can lead to the exfiltration of credentials and full administrative control (SuperUser) of the server.
decode_sequence_of() in lib/krb5/asn.1/asn1_encode.c in MIT Kerberos 5 (aka krb5) 1.11 and later grows the decoded element array one entry at a time, which allows remote attackers to cause a denial of service (CPU consumption in the KDC) by sending an unauthenticated AS-REQ or TGS-REQ with a large number of elements in a SEQUENCE OF field over TCP.
The AUTH_GSSAPI handler in lib/rpc/svc_auth_gssapi.c in MIT Kerberos 5 (aka krb5) 1.5.2 and later allows remote attackers to cause a denial of service (memory exhaustion in kadmind) by sending repeated failed AUTH_GSSAPI_INIT requests. Each failed request allocates client state that is only freed after a 15-minute expiration timeout, allowing an attacker to accumulate memory faster than it is reclaimed.
clean_client() in lib/rpc/svc_auth_gssapi.c in MIT Kerberos 5 (aka krb5) restarts its scan from the head of the client list after each removal, resulting in quadratic CPU cost. Remote attackers can cause a denial of service (CPU consumption in kadmind) by accumulating a large number of AUTH_GSSAPI client entries.
The GSS-RPC transport layer in MIT Kerberos 5 (aka krb5) 1.4 and later does not release the previous authentication context when a client switches from an RPCSEC_GSS or AUTH_GSSAPI flavor to a non-GSS flavor on the same TCP connection. This allows remote attackers to cause a denial of service (memory exhaustion in kadmind) by repeatedly establishing and abandoning GSS authentication contexts.
clnttcp_call() in lib/rpc/clnt_tcp.c in MIT Kerberos 5 (aka krb5) does not free the RPC reply verifier between retries, which allows remote attackers to cause a denial of service (memory leak in GSS-RPC client programs) by injecting RPC replies with mismatched XIDs or by triggering authentication retries.
Earn your free CTEM certification.
Learn to scope, prioritize, validate and mobilize fixes for CVEs like CVE-2026-112321 with a free CTEM certification.
Beginner / Practitioner / Program Leader
Explore certifications