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Once CellApplication · Once Cell Project

CVE-2019-16141

HIGH · 7.5 CVSS v3.1 Published 2019-09-09
Fix available
A fix is available. Upgrade to 1.0.1 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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 · unedited
An issue was discovered in the once_cell crate before 1.0.1 for Rust. There is a panic during initialization of Lazy.

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 confidence

The once_cell crate before version 1.0.1 for Rust contains a vulnerability where a panic occurs during the initialization of the Lazy primitive. This could lead to denial of service in applications relying on lazy initialization.

MitigationUpgrade the once_cell crate to version 1.0.1 or later to resolve the initialization panic issue.

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
Once CellApplication
Affected:>= 0.2.6, < 1.0.1

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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 checks

Work through these to decide whether this CVE applies to you.

  1. Locate the once_cell crate version in your project
    Search your project's Cargo.lock file for the once_cell entry and note the version number listed after 'name = "once_cell"'
    Affected if The version shown is 0.2.6 or higher but lower than 1.0.1 (for example 0.3.0, 0.4.0, 1.0.0)
  2. Check Cargo.toml for direct once_cell dependency
    Look in your Cargo.toml file under [dependencies] for any line containing once_cell and check the version specifier
    Affected if The specified version range includes versions below 1.0.1 (such as "0.2", "0.3", "0.4", ">=0.2.6")
  3. Verify your build uses the vulnerable version
    Run `cargo tree -p once_cell` to display the exact version of once_cell being used in your current build
    Affected if The output shows a version in the range 0.2.6 through 1.0.0
  4. Confirm Lazy primitive usage in your code
    Search your source files for imports or usage of `once_cell::sync::Lazy` or `once_cell::unsync::Lazy`
    Affected if Your code uses the Lazy type and the crate version is vulnerable per steps 1-3

You are affected if the once_cell crate version in your build is 0.2.6 or higher but below 1.0.1 and your code uses the Lazy primitive for lazy initialization.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Upgrade available Upgrade to 1.0.1 or later
Fixed in 1.0.1
Interim mitigation

Upgrade the once_cell crate to version 1.0.1 or later to resolve the initialization panic issue.

Fix this in Once Cell Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,340
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,144.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2019-16141 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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