CVE-2020-36456Public exploit

Memory corruption via unconstrained CopyCell Send implementation

Published Aug 8, 2021 · Updated Aug 4, 2024

A race condition in toolshed 0.8.1 and earlier allows attackers to trigger memory corruption through concurrent CopyCell use. CopyCell implements Send when T is merely Copy, so a copied reference to interior-mutable data can cross thread boundaries without the required Sync guarantee. Exploitation requires an application to store such a reference and use the resulting CopyCell across threads; concurrent access can corrupt program state or crash the process.

CVSS severity8.1
High
EPSS probability1.10%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A race condition in toolshed 0.8.1 and earlier allows attackers to trigger memory corruption through concurrent CopyCell use. CopyCell implements Send when T is merely Copy, so a copied reference to interior-mutable data can cross thread boundaries without the required Sync guarantee. Exploitation requires an application to store such a reference and use the resulting CopyCell across threads; concurrent access can corrupt program state or crash the process.

The record

CVE
CVE-2020-36456
Published
Aug 8, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-77, CWE-362
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Aug 8, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.1RustSec Advisory DatabaseCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
8.1NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
8.1GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-77Improper Neutralization of Special Elements used in a Command ('Command Injection')
CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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