CVE-2021-41641Public exploit

Sandbox escape via unchecked symlink permissions

Published Jun 12, 2022 · Updated Aug 4, 2024

Link following in Deno before 1.16.0 allows local users to read or write arbitrary files through a permitted symlink. The Deno.symlink and Deno.symlinkSync operations checked write access only for the new link path instead of requiring unrestricted read and write permissions, allowing the link to resolve beyond permitted directories. Exploitation requires code execution under Deno with specific write access, and the resulting sandbox escape is limited to host-file access available through the crafted link.

CVSS severity8.4
High
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Link following in Deno before 1.16.0 allows local users to read or write arbitrary files through a permitted symlink. The Deno.symlink and Deno.symlinkSync operations checked write access only for the new link path instead of requiring unrestricted read and write permissions, allowing the link to resolve beyond permitted directories. Exploitation requires code execution under Deno with specific write access, and the resulting sandbox escape is limited to host-file access available through the crafted link.

The record

CVE
CVE-2021-41641
Published
Jun 12, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-59, CAPEC-132, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 12, 2022CVE 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

3.6NIST NVDAV:L/AC:L/Au:N/C:P/I:P/A:N
8.4NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
8.4GitHub Advisory DatabaseCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/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.

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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-59Improper Link Resolution Before File Access ('Link Following')
CAPEC-132Symlink Attack
T1068Exploitation for Privilege Escalation

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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