CVE-2017-7549 — instack-undercloud
MEDIUMCVE-2017-7549 is a medium-severity (CVSS 6.4) CWE-377 vulnerability in instack-undercloud. No vendor fix is recorded yet; mitigation options are listed below.
instack-undercloud vulnerable to symlink attack on tmp files
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2017-7549 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
instack-undercloudReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | instack-undercloud | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for instack-undercloud, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of instack-undercloud has shipped for CVE-2017-7549 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2017-7549 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2017-7549. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux OpenStack Platform director 7.0 for RHEL 7 | instack-undercloud-0:2.1.2-41.el7ost | RHSA-2017:2693 |
| Red Hat OpenStack Platform 10.0 (Newton) | instack-undercloud-0:5.3.0-3.el7ost | RHSA-2017:2649 |
| Red Hat OpenStack Platform 11.0 (Ocata) | instack-undercloud-0:6.1.0-3.el7ost | RHSA-2017:2726 |
| Red Hat OpenStack Platform 8.0 (Liberty) director | instack-undercloud-0:2.2.7-10.el7ost | RHSA-2017:2687 |
| Red Hat OpenStack Platform 9.0 (Mitaka) director | instack-undercloud-0:4.0.0-17.el7ost | RHSA-2017:2557 |
Frequently Asked Questions
Is CVE-2017-7549 in your dependencies?
O3 Security finds CVE-2017-7549 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.