---
id: "CVE-2026-112320"
page: "https://infrastack.ai/live/CVE-2026-112320"
kind: "vulnerability"
aliases: ["CVE-2026-112320"]
title: "MIT Kerberos: GSS-RPC leaks auth contexts, letting remote clients exhaust kadmind memory"
severity: "high"
cvss: 7.5
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: [{"name": "krb5", "fixed": ["1.22.3"], "affected": ">= 1.4, < 1.22.3", "ecosystem": "vendor"}]
ecosystems: []
tags: ["infrastructure", "kadmind", "kerberos", "mit-krb5", "self-hosted"]
not_affected_if: ["client-only", "kadmind-not-exposed"]
published_at: "2026-11-09T19:16:40+00:00"
first_seen_at: "2026-11-09T19:28:13+00:00"
updated_at: "2026-11-09T19:37:08+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-112320", "first_seen_at": "2026-11-09T19:28:13+00:00"}, {"source": "analyst", "url": "https://web.mit.edu/kerberos/advisories/MITKRB5-SA-2026-001.txt", "first_seen_at": "2026-11-09T19:37:08+00:00", "cites": ["https://web.mit.edu/kerberos/advisories/MITKRB5-SA-2026-001.txt"]}]
exploit_sources: []
---

# MIT Kerberos: GSS-RPC leaks auth contexts, letting remote clients exhaust kadmind memory

Link for people: https://infrastack.ai/live/CVE-2026-112320 (this .md is for agents)

MIT Kerberos 5 (krb5) 1.4 and later does not free the previous GSS authentication context when a client switches flavor on the same TCP connection. Remote attackers can repeat this to exhaust memory in kadmind, causing denial of service.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:krb5 affected >= 1.4, < 1.22.3 fixed 1.22.3

## How to check

- Check the krb5 version: krb5-config --version or kadmind -h/package manager; versions below 1.22.3 are in scope (advisory does not list affected ranges; 1.4+ per NVD).
- Check whether kadmind (TCP 749, also kpasswd 464) is reachable from untrusted networks. Client-only hosts and KDCs without kadmind are not affected.

## Fix

Upgrade MIT krb5 to 1.22.3 (MITKRB5-SA-2026-001); update the primary kadmin server first.

## Timeline

- 2026-11-09T19:28:13+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-112320
- 2026-11-09T19:37:08+00:00 analyst https://web.mit.edu/kerberos/advisories/MITKRB5-SA-2026-001.txt — MIT advisory MITKRB5-SA-2026-001 lists CVE-2026-112320 as DoS, fixed in 1.22.3; no workarounds given; affected range lower bound 1.4 from NVD description, not the advisory. Advisory read via WebFetch summary (no per-CVE text), so exposure requirement (network reach to kadmind) is inferred from the NVD description. web-cli unavailable in this run; X not checked.

## Documents

- [advisory] MITKRB5-SA-2026-001: Multiple vulnerabilities fixed in 1.22.3 https://web.mit.edu/kerberos/advisories/MITKRB5-SA-2026-001.txt

## From the sources

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.

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