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Fencer Intel
high 7.8

CVE-2021-31566 json

An improper link resolution flaw can occur while extracting an archive leading to changing modes,...

published 4y ago modified 7d ago also EUVD-2021-18460 , JLSEC-2025-236

cvss
7.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 33%
public exploits
0
none known

Summary

An improper link resolution flaw can occur while extracting an archive leading to changing modes, times, access control lists, and flags of a file outside of the archive. An attacker may provide a malicious archive to a victim user, who would trigger this flaw when trying to extract the archive. A local attacker may use this flaw to gain more privileges in a system.

Patch / fix

  • julia LibArchive_jll 3.5.2+0
  • libarchive libarchive 3.5.2
  • splunk universal_forwarder 8.2.12, 9.0.6
  • libarchive Debian 14, Debian 13, Debian 12 3.5.2-1

debian advisories DEBIAN-CVE-2021-31566

  • libarchive Ubuntu 20.04 LTS 3.4.0-2ubuntu1.1

ubuntu advisories UBUNTU-CVE-2021-31566

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libarchive RHEL 8 3.3.3-3.el8_5
  • bsdtar RHEL 8 3.3.3-3.el8_5

red hat advisories RHSA-2022:0892

  • libarchive SLE Module for Development Tools 15 SP4, SLE Module for Basesystem 15 SP4, SLE Micro 5.3 +1 more 3.5.1-150400.3.9.1
  • libarchive SLE Module for Development Tools 15 SP3, SLE Module for Basesystem 15 SP3, openSUSE Leap 15.3 3.4.2-150200.4.12.1

suse advisories SUSE-SU-2022:3936-1SUSE-SU-2022:3935-1

  • bsdtar openSUSE Tumbleweed 3.6.0-1.1

opensuse advisories openSUSE-SU-2024:11894-1

  • libarchive AlmaLinux 8 3.3.3-3.el8_5
  • bsdtar AlmaLinux 8 3.3.3-3.el8_5

almalinux advisories ALSA-2022:0892

  • libarchive Rocky Linux 8 3.3.3-3.el8_5

rocky linux advisories RLSA-2022:0892

  • libarchive Alpine 3.14, Alpine 3.13 3.5.3-r0

alpine advisories ALPINE-CVE-2021-31566

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Is CVE-2021-31566 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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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-2021-31566 updated cvss 7.1

libarchive: symbolic links incorrectly followed when changing modes, times, ACL and flags of a file while extracting an archive

  • Red Hat Enterprise Linux 6 libarchive Red Hat Enterprise Linux 7 bsdtar, bsdcpio, libarchive
    affected: no fix planned “Out of support scope”
  • Red Hat CodeReady Linux Builder (v. 8) bsdcat-debuginfo 3.3.3-3.el8_5, bsdtar-debuginfo 3.3.3-3.el8_5, libarchive-devel 3.3.3-3.el8_5, bsdcpio-debuginfo 3.3.3-3.el8_5, libarchive-debuginfo 3.3.3-3.el8_5, libarchive-debugsource 3.3.3-3.el8_5 Red Hat Enterprise Linux BaseOS (v. 8) bsdtar 3.3.3-3.el8_5, libarchive 3.3.3-3.el8_5
    fixed: vendor fix RHSA-2022:0892
  • Red Hat Enterprise Linux 9 bsdtar, libarchive
    not affected: vulnerable code not present

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
partial
Assessed
7d ago

Exploit prediction

0.39% chance of exploitation in the next 30 days, higher than 33% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
OSV 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
julia LibArchive_jll
<3.5.2+0
3.5.2+0

Affected products

  • n/a libarchive

Classification

Weakness
  • CWE-59 Improper Link Resolution Before File Access

References

Sources

Fencer Intel 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.