CVE-2023-38037 is a medium-severity (CVSS 5.5) CWE-732 vulnerability in activesupport. A fix is available for activesupport — see the affected versions and patch details below.
Active Support Possibly Discloses Locally Encrypted Files
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-38037.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
activesupport💎activesupportReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
There is a possible file disclosure of locally encrypted files in Active Support. This vulnerability has been assigned the CVE identifier CVE-2023-38037.
Versions Affected: >= 5.2.0 Not affected: < 5.2.0 Fixed Versions: 7.0.7.1, 6.1.7.5
Impact
ActiveSupport::EncryptedFile writes contents that will be encrypted to a temporary file. The temporary file’s permissions are defaulted to the user’s current umask settings, meaning that it’s possible for other users on the same system to read the contents of the temporary file.
Attackers that have access to the file system could possibly read the contents of this temporary file while a user is editing it.
All users running an affected release should either upgrade or use one of the workarounds immediately.
Releases
The fixed releases are available at the normal locations.
Workarounds
To work around this issue, you can set your umask to be more restrictive like this:
$ umask 0077
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | activesupport | ≥ 5.2.0&&< 6.1.7.5 | 6.1.7.5bundle update activesupport --conservative |
| 💎RubyGems | activesupport | ≥ 7.0.0&&< 7.0.7.1 | 7.0.7.1bundle update activesupport --conservative |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for activesupport, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update activesupport to 6.1.7.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-38037 is resolved across your whole dependency graph.
Workarounds
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.
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.
To work around this issue, users can set their umask to be more restrictive: $ umask 0077Source: Red Hat security advisory for CVE-2023-38037 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Satellite 6.15 for RHEL 8 | rubygem-activesupport-0:6.1.7.6-1.el8sat | RHSA-2024:2010 |
| RHOL-5.7-RHEL-8 | openshift-logging/fluentd-rhel8:v1.14.6-203 | RHSA-2024:0268 |
| RHOL-5.8-RHEL-9 | openshift-logging/fluentd-rhel9:v5.8.1-9 | RHSA-2023:7720 |
Frequently Asked Questions
Is CVE-2023-38037 in your dependencies?
Find it across RubyGems, including transitive dependencies.