CVE-2023-38037
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedActiveSupport::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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceActiveSupport::EncryptedFile in Ruby on Rails writes content intended for encryption to a temporary file using the user's default umask permissions. This allows other local users on the same system to read the unencrypted sensitive content from the temp file while a user is editing an encrypted file.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- High
- Privileges
- Low
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- Low
- Availability
- Low
CVSS:3.0/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:L/A:L
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify Rails versionRun `rails --version` or check the Gemfile.lock for the rails gem versionAffected if The installed Rails version predates the patched release containing the fix for this vulnerability
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Check for ActiveSupport::EncryptedFile usageSearch codebase for `ActiveSupport::EncryptedFile`, `config/credentials.yml.enc`, or `config/master.key` which indicate encrypted file feature is in useAffected if The application uses Rails encrypted file features (credentials, secrets, or custom encrypted files)
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Verify umask settingRun `umask` in the shell where encrypted files are edited, or check application initialization files for umask configurationAffected if The umask is set to a permissive value (greater than 0077) or not explicitly set to a restrictive value before editing encrypted files
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Confirm multi-user system environmentCheck system for multiple local user accounts using `getent passwd | grep -v '^noplus:'` or `cat /etc/passwd`Affected if More than one local user account exists on the system, allowing the temp file exposure to be exploitable by another local user
A user is affected if running a vulnerable Rails version with ActiveSupport::EncryptedFile features enabled, while other local users have access to the same system and the umask does not restrict file permissions during encrypted file editing.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataUpgrade to a patched Rails version or set a restrictive umask (e.g., umask 0077) before editing encrypted files as a workaround.
- Consultation2.0 h
- Implementation3.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,040.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-38037 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2023-38037 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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