CVE-2020-13845
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 3.0 through 3.5 has Improper Validation of an Integrity Check Value. Image integrity is not validated when an ECL policy is enforced. The fingerprint required by the ECL is compared against the signature object descriptor(s) in the SIF file, rather than to a cryptographically validated signature.
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 confidenceIn Sylabs Singularity 3.0-3.5, when an ECL (Execution Control List) policy is enforced, the system validates image integrity by comparing the required fingerprint against signature object descriptors stored in the SIF file header, rather than verifying against a cryptographically validated signature. This allows attackers to potentially bypass integrity checks by modifying the SIF file while preserving the signature descriptors, since the actual cryptographic signature validation is never performed.
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>= 3.0.0, <= 3.5.0CVSS 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
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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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Check installed Singularity versionRun `singularity --version` or check the binary path with `which singularity` and `singularity version`Affected if Version is between 3.0.0 and 3.5.0 inclusive
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Locate Singularity configuration fileFind singularity.conf typically at /etc/singularity/singularity.conf or via `singularity config global` commandAffected if Configuration file exists and ECL is configured
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Verify if ECL is enabled in configurationSearch for `ecl` or `execution control list` in singularity.conf, or run `singularity config global --verbose` and look for ECL-related settingsAffected if ECL is enabled (not commented out or set to a policy mode)
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Confirm ECL enforcement modeCheck if ECL is set to enforce signatures - look for allowlist or denylist configuration with fingerprint settings in the config fileAffected if ECL policy is actively enforcing (not disabled or set to 'none')
User is affected if Singularity version is 3.0.0-3.5.0 AND ECL policy is enabled/enforced, because the cryptographic signature validation is bypassed in these versions.
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 Singularity 3.6 or later where the signature validation logic was corrected to verify against cryptographically validated signatures rather than raw descriptor values. Alternatively, avoid relying solely on ECL policies for security-critical workloads until patched.
- 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-2020-13845 — 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-2020-13845 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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