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CVE Record

CVE-2020-36442: An issue was discovered in the beef crate before 0.5.0 for Rust.

An issue was discovered in the beef crate before 0.5.0 for Rust. beef::Cow has no Sync bound on its Send trait.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2020-36442 affects the Rust beef crate before 0.5.0. A concurrency safety rule was missing for beef::Cow, which may allow code to be treated as safe to send across threads when its contents are not safely shareable. Business urgency depends on whether affected Rust applications use this crate in threaded paths.

Executive priority

Treat this as a dependency hygiene issue unless critical Rust services use vulnerable beef versions in concurrent code. Prioritize inventory and upgrade during normal patch cycles, escalating if the crate appears in externally exposed or safety-sensitive services.

Technical view

The issue is an incorrect Send implementation for beef::Cow without requiring the underlying type to satisfy Sync. In Rust terms, this is a soundness flaw in trait bounds that can undermine thread-safety guarantees. The public bundle does not provide CVSS, CWE, proof-of-concept details, or specific downstream affected products.

Likely exposure

Exposure is likely limited to Rust projects that depend directly or transitively on beef versions before 0.5.0. Risk is higher where beef::Cow values are used across thread boundaries or in concurrent application logic. No CPEs or named downstream products are provided.

Exploitation context

The source bundle does not indicate active exploitation, and the CVE is not listed as KEV. The available evidence describes a Rust type-safety issue, not a remote attack path. Practical exploitability depends on application-specific use of the crate and concurrency behavior.

Researcher notes

The evidence is sparse: no CVSS, CWE, exploit details, or affected downstream products are listed. The key technical point is Rust trait-bound unsoundness around Send and Sync. Researchers should focus on dependency presence, version resolution, and whether application code exercises cross-thread beef::Cow behavior.

Mitigation direction

  • Inventory Rust dependencies for beef versions before 0.5.0.
  • Upgrade beef to 0.5.0 or later where compatible.
  • Review RustSec advisory guidance before deployment.
  • Rebuild and redeploy affected Rust applications after dependency updates.
  • Monitor dependency scanners for transitive beef usage.

Validation and detection

  • Check Cargo.lock for beef package versions below 0.5.0.
  • Run cargo tree to identify direct or transitive beef dependency paths.
  • Confirm updated builds resolve beef to 0.5.0 or later.
  • Review code paths that move beef::Cow values across threads.
  • Run unit and concurrency regression tests after upgrading.
Prepared
Confidence
medium
Sources
4

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
3Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

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