CVE-2021-27117Public exploit

Arbitrary file overwrite via symlinked CPU profile

Published Apr 5, 2022 · Updated Aug 3, 2024

Symlink following in Beego through 2.0.2 allows local users to overwrite files writable by the Beego process via a crafted CPU-profile link. GetCPUProfile in core/admin/profile.go builds the predictable cpu-.pprof name and passes it to os.Create without rejecting an existing symbolic link. An attacker needs local filesystem access to place the link before profiling starts; the redirected write corrupts the target with profiling data under the process's permissions.

CVSS severity7.8
High
EPSS probability0.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Symlink following in Beego through 2.0.2 allows local users to overwrite files writable by the Beego process via a crafted CPU-profile link. GetCPUProfile in core/admin/profile.go builds the predictable cpu-.pprof name and passes it to os.Create without rejecting an existing symbolic link. An attacker needs local filesystem access to place the link before profiling starts; the redirected write corrupts the target with profiling data under the process's permissions.

The record

CVE
CVE-2021-27117
Published
Apr 5, 2022
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-59, CAPEC-132, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 5, 2022CVE 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?

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

7.2NVDAV:L/AC:L/Au:N/C:C/I:C/A:C
7.8MITRECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8NVDCVSS:3.1/AV:L/AC:L/PR:L/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.

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)
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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