CVE-2026-112320
Description
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.
Statement
This vulnerability is rated with an Important severity because it enables unauthenticated remote attackers to trigger unbounded heap memory exhaustion, leading to a service crash or denial of service across exposed RPC services. In Red Hat Enterprise Linux environments, exploitation requires direct network reachability to daemons utilizing the internal GSS-RPC transport over persistent TCP connections, such as the Kerberos administration server (kadmind). Because the flaw does not facilitate remote code execution or unauthorized access to sensitive Kerberos database records, it does not warrant a Critical rating.
Mitigation
Restrict network access to kadmind to trusted hosts, or disable it in favor of kadmin.local server-side command line tool for administration operations if possible.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (Other); DoS: Resource Consumption (Memory); DoS: Resource Consumption (CPU)
An attacker that can influence the allocation of resources that are not properly released could deplete the available resource pool and prevent all other processes from accessing the same type of resource. Frequently-affected resources include memory, CPU, disk space, power or battery, etc.
Acknowledgements
This issue was discovered by Found by AISLE in partnership with Red Hat.
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