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Vulnerability record · public intelligence
CVE-2020-15254
HIGH

crossbeam-channel Undefined Behavior before v0.4.4

Published Oct 16, 2020 · Updated Nov 3, 2026

Severity · CVSSHIGH · Not scored
Known exploitationNot listed
EPSS / likelihood2.70%
QFinch risk scoreNot available

Original summary

Normalized public record · Updated Nov 3, 2026

crossbeam-channel Undefined Behavior before v0.4.4

Publisher and source text is retained separately from QFinch interpretation.

QFinch assessment

The affected version of this crate's the `bounded` channel incorrectly assumes that `Vec::from_iter` has allocated capacity that same as the number of iterator elements. `Vec::from_iter` does not actually guarantee that and may allocate extra memory. The destructor of the `bounded` channel reconstructs `Vec` from the raw pointer based on the incorrect assumes described above. This is unsound and causing deallocation with the incorrect capacity when `Vec::from_iter` has allocated different sizes with the number of iterator elements.

Potential impact

The affected version of this crate's the bounded channel incorrectly assumes that Vec::fromiter has allocated capacity that same as the number of iterator elements. Vec::fromiter does not actually guarantee that and may allocate extra memory. The destructor of the bounded channel reconstructs Vec from the raw pointer based on the incorrect assumes described above. This is unsound and causing deallocation with the incorrect capacity when Vec::fromiter has allocated different sizes with the number of iterator elements.

Evidence: public source records

Affected products

Affected scope reported by the available public evidence
Affected package, product or rangeFix status
Consult the referenced vendor advisory for affected versions.Consult source advisory

Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.

Remediation

Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.

  1. Confirm the affected product and reachable code path exist in your environment.
  2. Apply the vendor-supported patch or mitigation from the primary advisory.
  3. Rescan the exact deployed revision and retain verification evidence.
Review primary references

Evidence coverage

FIRST-EPSSCVE-LIST-V5
SSVC priority
MEDIUM
Confidence
Not available
Aliases
None reported

Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.

Sources and record history

  1. Security advisory ↗
  2. Source repository ↗
  3. Source repository ↗
  4. Source repository ↗

Record history

Published Oct 16, 2020 · Last refreshed Nov 3, 2026