CVE-2018-12021
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 · uneditedSingularity 2.3.0 through 2.5.1 is affected by an incorrect access control on systems supporting overlay file system. When using the overlay option, a malicious user may access sensitive information by exploiting a few specific Singularity features.
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 · moderate confidenceSingularity container runtime versions 2.3.0 through 2.5.1 have an incorrect access control vulnerability on systems supporting the overlay filesystem. When the overlay option is enabled, a malicious user can exploit specific Singularity features to bypass access controls and read sensitive information that should be protected.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data>= 2.3.0, <= 2.5.1CVSS 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
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
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 Singularity installationRun `singularity --version` or `singularity version` to confirm Singularity is installed and retrieve the version number.Affected if Command fails or Singularity is not installed (not affected in the latter case)
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Determine installed Singularity versionCompare the version output from the previous step against the affected range: >= 2.3.0 and <= 2.5.1.Affected if Version falls within 2.3.0 to 2.5.1 inclusive
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Check if overlay filesystem is supportedVerify that the system kernel supports overlay filesystem (typically `/proc/filesystems` contains 'overlay') or that Singularity was built with overlay support.Affected if Overlay filesystem is supported on the system
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Identify overlay option usageReview Singularity container definitions, command invocations, and configuration files (e.g., singularity.conf) for the presence of the `--overlay` option or overlay-related settings.Affected if Overlay option is explicitly enabled or used in container runs
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Assess user privilege contextDetermine if unprivileged or less-privileged users have access to run Singularity containers with overlay features on the system.Affected if Non-privileged users can invoke Singularity with overlay capabilities
A system is affected if it runs Singularity version 2.3.0 through 2.5.1 with the overlay filesystem option enabled, allowing potential bypass of access controls.
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 Singularity to a version beyond 2.5.1 where the access control issue is fixed. If immediate upgrade is not possible, avoid using the overlay option or implement additional access controls on affected systems.
- Consultation4.0 h
- Implementation8.0 h
- Testing12.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-12021 — 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-2018-12021 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
- No spam, self-promotion, credentials, or personal data