---
id: "CVE-2026-119079"
page: "https://infrastack.ai/live/CVE-2026-119079"
kind: "vulnerability"
aliases: ["CVE-2026-119079"]
title: "MIT Kerberos: unauthenticated requests over TCP can exhaust KDC CPU"
severity: "high"
cvss: 7.5
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: [{"name": "krb5", "fixed": ["1.22.3"], "affected": "< 1.22.3", "ecosystem": "vendor"}]
ecosystems: []
tags: ["active-directory-adjacent", "infrastructure", "kdc", "kerberos", "mit-kerberos", "self-hosted"]
not_affected_if: ["active-directory-only", "managed-hosting", "no-kdc-running", "udp-only"]
published_at: "2026-11-09T19:16:43+00:00"
first_seen_at: "2026-11-09T19:28:13+00:00"
updated_at: "2026-11-09T19:36:11+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-119079", "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": "2026-11-09T19:36:11+00:00", "cites": ["https://web.mit.edu/kerberos/advisories/MITKRB5-SA-2026-001.txt"]}]
exploit_sources: []
---

# MIT Kerberos: unauthenticated requests over TCP can exhaust KDC CPU

Link for people: https://infrastack.ai/live/CVE-2026-119079 (this .md is for agents)

MIT Kerberos 5 (krb5) 1.11 and later grows a decoded element array one entry at a time in decode_sequence_of(). A remote attacker can send an unauthenticated AS-REQ or TGS-REQ over TCP with a very large SEQUENCE OF field to consume CPU on the KDC and cause denial of service.

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

## Affected

- vendor:krb5 affected < 1.22.3 fixed 1.22.3

## How to check

Run a KDC? Check the version: 'krb5-config --version' or your package manager (e.g. rpm -q krb5-server, dpkg -l krb5-kdc). Anything older than 1.22.3 that runs krb5kdc and accepts TCP (port 88) is in scope; the advisory does not give an exact lower bound (NVD summary says 1.11 and later). Distro builds may carry the patch without the version number changing.

## Fix

Upgrade MIT krb5 to 1.22.3 (MITKRB5-SA-2026-001). Distro packages: install your vendor's backport of this advisory.

## Timeline

- 2026-11-09T19:28:13+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-119079
- 2026-11-09T19:36:11+00:00 analyst https://web.mit.edu/kerberos/advisories/MITKRB5-SA-2026-001.txt — MIT advisory MITKRB5-SA-2026-001 lists this CVE under Denial of Service, fixed in 1.22.3; it gives no affected-version lower bound and no workaround. The decode_sequence_of detail and 1.11+ range come from the NVD summary only, not verified. Exa search and X were not used (credits exhausted); NVD page did not load. No exploitation or PoC found.

## 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

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.

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