CVE-2020-36204Public exploit

Process crash via unsound TreeFocus thread traits

Published Jan 22, 2021 · Updated Aug 4, 2024

A data-race flaw in im 12.0.0 through 15.0.0 allows local users to crash a consuming process through safe Rust code. TreeFocus unconditionally implements Send and Sync without requiring its element type to support the corresponding cross-thread trait, allowing non-thread-safe values to cross thread boundaries. Exploitation requires a consumer to extract TreeFocus from Focus and race access across threads; typical callers that use only Focus are unaffected, and the demonstrated consequence is a SIGSEGV crash.

CVSS severity4.7
Medium
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A data-race flaw in im 12.0.0 through 15.0.0 allows local users to crash a consuming process through safe Rust code. TreeFocus unconditionally implements Send and Sync without requiring its element type to support the corresponding cross-thread trait, allowing non-thread-safe values to cross thread boundaries. Exploitation requires a consumer to extract TreeFocus from Focus and race access across threads; typical callers that use only Focus are unaffected, and the demonstrated consequence is a SIGSEGV crash.

The record

CVE
CVE-2020-36204
Published
Jan 22, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-662, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 22, 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 vectorlocal
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

1.9NIST NVDAV:L/AC:M/Au:N/C:N/I:N/A:P
4.7GitHub Advisory DatabaseCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
4.7NIST NVDCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
4.7RustSecCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

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.

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No observations available

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

Weakness, pattern, technique

CWE-662Improper Synchronization
T1499.004Endpoint Denial of Service: Application or System Exploitation

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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