---
title: "CVE-2017-6594\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2017-6594?format=md
keywords: index, follow
---

# CVE-2017-6594

Publication date 28 August 2017

Last updated 25 August 2025

---

Ubuntu priority

**Low**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**7.5 · High**

[Score breakdown](https://ubuntu.com/security/CVE-2017-6594?format=md#impact-score)

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## Description

The transit path validation code in Heimdal before 7.3 might allow
attackers to bypass the capath policy protection mechanism by leveraging
failure to add the previous hop realm to the transit path of issued
tickets.

[Read the notes from the security team](https://ubuntu.com/security/CVE-2017-6594?format=md#notes)

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| heimdal | 22.10 kinetic | Not affected |
| 22.04 LTS jammy | Not affected |
| 21.10 impish | Not affected |
| 21.04 hirsute | Not affected |
| 20.10 groovy | Not affected |
| 20.04 LTS focal | Not affected |
| 19.10 eoan | Not affected |
| 19.04 disco | Not affected |
| 18.10 cosmic | Not affected |
| 18.04 LTS bionic | Not affected |
| 17.10 artful | Not affected |
| 17.04 zesty | Ignored end of life |
| 16.10 yakkety | Ignored end of life |
| 16.04 LTS xenial | Ignored end of standard support, was needed |
| 14.04 LTS trusty | Ignored end of standard support |
| 12.04 LTS precise | Ignored end of life |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)
* [Patch details](https://ubuntu.com/security/CVE-2017-6594?format=md#patch-details)

## Notes

---

### [ratliff](https://launchpad.net/~ratliff)

Upstream: "[the fix] may break sites that rely on the bug."

---

### [mdeslaur](https://launchpad.net/~mdeslaur)

heimdal-kdc package is in universe

---

### [ccdm94](https://launchpad.net/~ccdm94)

in the commit that fixes this issue, upstream mentions that
there might be applications that use this bug as a "feature"
when sometimes authenticating in cross-realm configurations,
meaning that applying the proposed fix could end up breaking
said applications. In order to avoid regressions for
applications that use heimdal in xenial and earlier, this
issue will be marked as ignored for those releases.

### Patch details

For informational purposes only. We recommend not to cherry-pick updates. [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)

| Package | Patch details |
| --- | --- |
| heimdal | * Upstream:   [b1e6991](https://github.com/heimdal/heimdal/commit/b1e699103f08d6a0ca46a122193c9da65f6cf837) |

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

7.5 · High

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Network |
  | Attack complexity | Low |
  | Privileges required | None |
  | User interaction | None |
  | Scope | Unchanged |
  | Confidentiality impact | None |
  | Integrity impact | High |
  | Availability impact | None |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 7.5 · High |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-6594)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2017-6594)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2017-6594)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2017-6594)

### Other references

* <https://www.cve.org/CVERecord?id=CVE-2017-6594>