CVE-2020-25040
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 · uneditedSylabs Singularity through 3.6.2 has Insecure Permissions on temporary directories used in explicit and implicit container build operations, a different vulnerability than CVE-2020-25039.
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 confidenceSylabs Singularity through version 3.6.2 creates temporary directories with insecure permissions during container build operations (both explicit and implicit). This allows local attackers to potentially access or manipulate sensitive container build artifacts in these temp directories due to overly permissive access controls.
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<= 3.6.2= 15.1= 15.2CVSS 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
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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 installation and versionRun 'singularity --version' or check the installed package version via package manager (e.g., 'rpm -q singularity' or 'dpkg -l singularity')Affected if The installed version is 3.6.2 or any earlier version (3.x series up to 3.6.2)
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Confirm container build functionality is in useReview whether users have access to or routinely execute 'singularity build' commands, or check for presence of build-related workflows or scripts in the environmentAffected if Container build operations are performed using Singularity on the system
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Inspect temporary directory permissions during buildRun 'singularity build --sandbox /tmp/testcontainer docker://alpine' as a test, then check permissions on /tmp or the specific temp directory created (e.g., 'ls -la /tmp | grep -i singu' or examine the temporary work directory used by Singularity)Affected if The temporary directories created during build have permissions allowing world-readable or world-writable access (e.g., 777 or overly broad ownership)
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Verify temp directory isolationExamine the Singularity configuration file (typically /etc/singularity/singularity.conf) for 'tmp dir' or 'temp directory' settings, and check if a dedicated temp directory with restricted permissions is configured versus using the system default /tmpAffected if Singularity is configured to use a shared or system default temp directory without restricted permissions
A system is affected if Singularity version 3.6.2 or earlier is installed and container build operations are performed, resulting in temp directories with overly permissive 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 patched version beyond 3.6.2. If immediate patching is not feasible, ensure container build operations run in isolated or sandboxed environments with restricted local access.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA3.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-25040 — 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-2020-25040 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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- Version or environment caveats, and links to real fixes
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