CVE-2020-15254

Undefined Behavior in bounded Crossbeam channel

CRITICAL
9.8
CVSS Score
Published: October 16, 2020 at 05:05 PM UTC
Updated: June 17, 2026 at 02:56 AM UTC
2 products affected across 2 vendorsCrossbeamProject Crossbeam

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Severity
CRITICAL9.8
Exploit prediction
EPSS 3%

Description

Crossbeam is a set of tools for concurrent programming. In crossbeam-channel before version 0.4.4, 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. This has been fixed in crossbeam-channel 0.4.4.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.4.4
Affected range stops below 0.4.4, so it looks safe — our inference, not a vendor statement
v < 0.4.4
Affected range stops below 0.4.4, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (4)

x_refsource_MISCPatchThird Party Advisory
https://github.com/RustSec/advisory-db/pull/425
x_refsource_MISCExploitThird Party Advisory
https://github.com/crossbeam-rs/crossbeam/issues/539
x_refsource_MISCExploitPatchThird Party Advisory
https://github.com/crossbeam-rs/crossbeam/pull/533

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-119CWE-401

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