CVE-2021-20197

Arbitrary file ownership via smart_rename symlink race

Published Mar 26, 2021 · Updated Dec 3, 2025

Symlink race in GNU Binutils 2.35 and earlier allows local users to gain ownership of arbitrary files through privileged utilities. The shared smart_rename() output path used by ar, objcopy, strip, and ranlib accepts a symlink destination while file replacement and ownership handling remain exposed to a race. Exploitation requires an unprivileged local user to influence the destination while a privileged user or script runs one of the affected utilities.

CVSS severity6.3
Medium
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Symlink race in GNU Binutils 2.35 and earlier allows local users to gain ownership of arbitrary files through privileged utilities. The shared smart_rename() output path used by ar, objcopy, strip, and ranlib accepts a symlink destination while file replacement and ownership handling remain exposed to a race. Exploitation requires an unprivileged local user to influence the destination while a privileged user or script runs one of the affected utilities.

The record

CVE
CVE-2021-20197
Published
Mar 26, 2021
Updated
Dec 3, 2025
Vendor
The GnuPG Project
Product
GNU Binutils
Classifications
CWE-59, CWE-362, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 26, 2021CVE publishedPublication date reported by the CVE source.
  2. Dec 3, 2025Record 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=binutils 2.35

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The GnuPG Project · GNU Binutilsversion=binutils 2.35

Published CVSS scores

3.3NVDAV:L/AC:M/Au:N/C:P/I:P/A:N
6.3CISA-ADPCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
6.3NVDCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/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 exploitUnconfirmed

Weakness, pattern, technique

CWE-59Improper Link Resolution Before File Access ('Link Following')
CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
T1068Exploitation for Privilege Escalation

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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