CVE-2017-7549: Instack undercloud Instack-undercloud Vulnerable To Symlink Attack Vulnerability

MODERATE
Advisory Identifier: GHSA-53wm-97p6-582f
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CVSS 6.4
CWE-377 CWE-59
Published
Advisory Summary

CVE-2017-7549 is a MODERATE (CVSS 6.4) instack-undercloud vulnerable to symlink attack vulnerability (CWE-377: Insecure Temporary File) affecting Instack undercloud libraries in the PyPI ecosystem. The issue involves instack-undercloud vulnerable to symlink attack on tmp files. Remediation is available in the latest vendor maintenance releases.

CVE-2017-7549 at a Glance

CVE Identifier CVE-2017-7549
GHSA Identifier GHSA-53wm-97p6-582f
Severity MODERATE
CVSS v3.1 Base Score 6.4
CWE Classification CWE-377: Insecure Temporary File
Affected Product Instack undercloud
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 6.4

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N).

Attack Vector Local (AV:L)
Attack Complexity High (AC:H)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Changed (S:C)
Confidentiality High (C:H)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2017-7549

To remediate this vulnerability, upgrade all affected Instack undercloud dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

instack-undercloud fixed: Latest secure release 
pip install instack-undercloud>=Latest secure release
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show instack-undercloud

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2017-7549, inspect your installed packages using pip:

pip show instack-undercloud

Analyze the terminal output to locate any version of Instack undercloud in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The pip show instack-undercloud command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-377: Insecure Temporary File, where creating and using insecure temporary files can leave application and system data vulnerable to attack. In Instack undercloud, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

A flaw was found in instack-undercloud 7.2.0 as packaged in Red Hat OpenStack Platform Pike, 6.1.0 as packaged in Red Hat OpenStack Platform Oacta, 5.3.0 as packaged in Red Hat OpenStack Newton, where pre-install and security policy scripts used insecure temporary files. A local user could exploit this flaw to conduct a symbolic-link attack, allowing them to overwrite the contents of arbitrary files.

CVE-2017-7549 Affected Instack undercloud Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
instack-undercloud
pypi/instack-undercloud
PyPI
≤ 7.2.0

References

NVD — CVE-2017-7549 NVD
https://nvd.nist.gov/vuln/detail/CVE-2017-7549
access.redhat.com/errata/rhsa-2017:25... WEB
https://access.redhat.com/errata/RHSA-2017:2557
access.redhat.com/errata/rhsa-2017:26... WEB
https://access.redhat.com/errata/RHSA-2017:2649
access.redhat.com/errata/rhsa-2017:26... WEB
https://access.redhat.com/errata/RHSA-2017:2687
access.redhat.com/errata/rhsa-2017:26... WEB
https://access.redhat.com/errata/RHSA-2017:2693
access.redhat.com/errata/rhsa-2017:27... WEB
https://access.redhat.com/errata/RHSA-2017:2726
Instack undercloud Security Information SECURITY
https://access.redhat.com/security/cve/CVE-2017-7549
bugzilla.redhat.com/show_bug.cgi WEB
https://bugzilla.redhat.com/show_bug.cgi?id=1477403
Instack undercloud Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/instack/PYSEC-2017-152.yaml
opendev.org/openstack/instack-u... WEB
https://opendev.org/openstack/instack-undercloud
Instack undercloud Security Information SECURITY
https://web.archive.org/web/20170907040549/http://www.securityfocus.com/bid/100407
Instack undercloud Security Information SECURITY
http://www.securityfocus.com/bid/100407

Frequently Asked Questions

What is CVE-2017-7549?
CVE-2017-7549 is a security vulnerability in Instack undercloud involving instack-undercloud vulnerable to symlink attack on tmp files under CWE-377: Insecure Temporary File.
Which Instack undercloud versions are affected?
Affected versions include releases prior to current release patches across affected packages: instack-undercloud.
What version fixes CVE-2017-7549?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is instack-undercloud affected?
Yes, instack-undercloud is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2017-7549?
CVE-2017-7549 has a CVSS v3.1 base score of 6.4 (MODERATE) with vector string CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N.
What CWE is associated with CVE-2017-7549?
CVE-2017-7549 is classified under CWE-377: Insecure Temporary File (Creating and using insecure temporary files can leave application and system data vulnerable to attack.).
How can I check PyPI dependencies for CVE-2017-7549?
Run the dependency tree command: 'pip show instack-undercloud'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-53wm-97p6-582f",
  "modified" : "2026-06-05T17:53:43Z",
  "published" : "2022-05-13T01:07:33Z",
  "aliases" : [ "CVE-2017-7549" ],
  "summary" : "instack-undercloud vulnerable to symlink attack on tmp files",
  "details" : "A flaw was found in instack-undercloud 7.2.0 as packaged in Red Hat OpenStack Platform Pike, 6.1.0 as packaged in Red Hat OpenStack Platform Oacta, 5.3.0 as packaged in Red Hat OpenStack Newton, where pre-install and security policy scripts used insecure temporary files. A local user could exploit this flaw to conduct a symbolic-link attack, allowing them to overwrite the contents of arbitrary files.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "instack-undercloud"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "7.2.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2017-7549"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2017:2557"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2017:2649"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2017:2687"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2017:2693"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2017:2726"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/security/cve/CVE-2017-7549"
  }, {
    "type" : "WEB",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=1477403"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/instack/PYSEC-2017-152.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://opendev.org/openstack/instack-undercloud"
  }, {
    "type" : "WEB",
    "url" : "https://web.archive.org/web/20170907040549/http://www.securityfocus.com/bid/100407"
  }, {
    "type" : "WEB",
    "url" : "http://www.securityfocus.com/bid/100407"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-377", "CWE-59" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2024-04-22T22:48:23Z",
    "nvd_published_at" : "2017-09-21T21:29:00Z"
  }
}