CVE-2020-27637Public exploitNetwork attack vector

Code execution via traversing package archive paths

Published Jan 12, 2021 · Updated Aug 4, 2024

Path traversal in the CRAN package manager in R 4.0.2 and earlier allows attackers to write arbitrary files through a crafted package archive. During install.packages() or R CMD INSTALL, package extraction accepts parent-directory components in archive member names and writes them outside the staging directory. A user must install an attacker-controlled source package; the write inherits the installer's privileges and can replace SSH keys or executable configuration for code execution.

CVSS severity9.8
Critical
EPSS probability2.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in the CRAN package manager in R 4.0.2 and earlier allows attackers to write arbitrary files through a crafted package archive. During install.packages() or R CMD INSTALL, package extraction accepts parent-directory components in archive member names and writes them outside the staging directory. A user must install an attacker-controlled source package; the write inherits the installer's privileges and can replace SSH keys or executable configuration for code execution.

The record

CVE
CVE-2020-27637
Published
Jan 12, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-22, T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 12, 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 vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8UbuntuCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
10.0NIST NVDAV:N/AC:L/Au:N/C:C/I:C/A:C
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1204.002User Execution: Malicious File

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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