Skip to content
Fencer Vulns
medium 6.3

CVE-2021-20197 json

There is an open race window when writing output in the following utilities in GNU binutils version 2.35 and earlier:ar, objcopy, strip, ra…

published 2021-03-26 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-7643

cvss
6.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 23%
public exploits
0
none known

Summary

There is an open race window when writing output in the following utilities in GNU binutils version 2.35 and earlier:ar, objcopy, strip, ranlib. When these utilities are run as a privileged user (presumably as part of a script updating binaries across different users), an unprivileged user can trick these utilities into getting ownership of arbitrary files through a symlink.

Patch / fix

  • binutils Debian 14, Debian 13, Debian 12 2.37-3

debian advisories DEBIAN-CVE-2021-20197

  • binutils RHEL 8 2.30-108.el8

red hat advisories RHSA-2021:4364

  • binutils SLES for SAP 15, SLES 15-LTSS, SLE High Performance Computing 15-LTSS +1 more 2.37-6.23.1
  • binutils SLES for SAP 15 SP1, SLES 15 SP1-LTSS, SLES 15 SP1-BCL +9 more 2.37-7.21.2
  • bpftrace SLE Module for Development Tools 15 SP3 0.11.4-3.2.1
  • binutils SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +11 more 2.37-9.39.1
  • cross-ppc-binutils SLE Software Development Kit 12 SP5 2.37-9.39.1
  • cross-spu-binutils SLE Software Development Kit 12 SP5 2.37-9.39.1

suse advisories SUSE-SU-2022:0934-1SUSE-SU-2021:3616-1SUSE-SU-2021:3593-1

  • binutils openSUSE Tumbleweed 2.37-1.3
  • binutils openSUSE Leap 15.2 2.37-lp152.4.9.1
  • bpftrace openSUSE Leap 15.2 0.11.4-lp152.2.7.1
  • cross-rx-binutils openSUSE Leap 15.2 2.37-lp152.4.9.1
  • cross-arm-binutils openSUSE Leap 15.2 2.37-lp152.4.9.1
  • cross-avr-binutils openSUSE Leap 15.2 2.37-lp152.4.9.1
  • cross-ppc-binutils openSUSE Leap 15.2 2.37-lp152.4.9.1
  • cross-spu-binutils openSUSE Leap 15.2 2.37-lp152.4.9.1

opensuse advisories openSUSE-SU-2024:10651-1openSUSE-SU-2021:1475-1openSUSE-SU-2021:3616-1

  • binutils Rocky Linux 8 2.30-108.el8

rocky linux advisories RLSA-2021:4364

  • crash Azure Linux 3.0 8.0.4-4

azure linux advisories AZL-41714

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

  • binutils Arch Linux 2.38-1

arch linux advisories AVG-1540

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-20197 updated cvss 4.2

binutils: Race window allows users to own arbitrary files

  • Red Hat Enterprise Linux 6 binutils Red Hat Enterprise Linux 7 binutils
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 gcc-toolset-9-binutils, gcc-toolset-10-binutils
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 9 binutils, binutils-gold
    affected: no fix available
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-dashboard-rhel9
    under investigation
  • Red Hat Enterprise Linux AppStream (v. 8) binutils-devel 2.30-108.el8, binutils-debuginfo 2.30-108.el8, binutils-debugsource 2.30-108.el8 Red Hat Enterprise Linux BaseOS (v. 8) binutils 2.30-108.el8
    fixed: vendor fix RHSA-2021:4364

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
11 mo ago

Exploit prediction

0.30% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 6.3 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
NVD 3.1 6.3 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
CNA 3.1 6.3 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
NVD 2.0 3.3 AV:L/AC:M/Au:N/C:P/I:P/A:N

Affected products

  • n/a binutils

Classification

Weakness
  • CWE-59 Improper Link Resolution Before File Access
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.