CVE-2021-32773Network attack vector

Sandbox escape via unconstrained module resolution

Published Jul 19, 2021 · Updated Aug 3, 2024

Sandbox escape in Racket before 8.2 allows attackers to control system functions via crafted modules supplied to an evaluator. The sandbox module resolver accepted reader and require paths from evaluated code without constraining syntactic module references, so system modules resolved attacker-created modules instead of intended dependencies. Reachability requires an application that evaluates attacker-supplied Racket code in-process; exploitation grants facilities that the sandbox intended to restrict.

CVSS severity6.1
Medium
EPSS probability0.87%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Sandbox escape in Racket before 8.2 allows attackers to control system functions via crafted modules supplied to an evaluator. The sandbox module resolver accepted reader and require paths from evaluated code without constraining syntactic module references, so system modules resolved attacker-created modules instead of intended dependencies. Reachability requires an application that evaluates attacker-supplied Racket code in-process; exploitation grants facilities that the sandbox intended to restrict.

The record

CVE
CVE-2021-32773
Published
Jul 19, 2021
Updated
Aug 3, 2024
Vendor
Racket
Product
Racket
Classifications
CWE-610, CWE-441
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 19, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 8.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Racket · Racketversion=< 8.2

Published CVSS scores

7.5NISTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
5.0NISTAV:N/AC:L/Au:N/C:N/I:P/A:N
6.1GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:H/A:N

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-610Externally Controlled Reference to a Resource in Another Sphere
CWE-441Unintended Proxy or Intermediary ('Confused Deputy')

Public exploit references

No public exploit references are available in this record.

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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