CVE-2021-31566

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.

Published: 2022-08-23 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-31566 is rated Moderate Risk (41.4/100): CVSS High severity, with low exploitation likelihood (EPSS 0.37%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-31566

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.03% 0.37% +0.33%
2 2025-11-21 0.07% 0.03% -0.04%
3 2025-11-18 — 0.07% —

Full EPSS history (11 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-31566

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 [email protected]

Weakness enumeration for CVE-2021-31566

OS Trackers for CVE-2021-31566

vendor priority summary link
alpine — CVE-2021-31566: 1 source package rows (libarchive); 15 state rows across 5 repos (3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 0, open 15. https://security.alpinelinux.org/vuln/CVE-2021-31566
debian not yet assigned CVE-2021-31566 not yet assigned priority: Debian including 1 source packages (libarchive), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-31566
gentoo high CVE-2021-31566: 1 GLSA(s) (202208-26), 1 atom(s) (app-arch/libarchive); latest impact high. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-31566
redhat medium — https://access.redhat.com/security/cve/CVE-2021-31566
suse medium — https://www.suse.com/security/cve/CVE-2021-31566/
ubuntu low CVE-2021-31566 low priority: Ubuntu including 1 source packages (libarchive), 15 status rows across 15 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 8, ignored 4, released 3. https://ubuntu.com/security/CVE-2021-31566

Affected software / configurations for CVE-2021-31566

Vendor Product Version Raw CPE
libarchive libarchive < 3.5.2 cpe:2.3:a:libarchive:libarchive:*:*:*:*:*:*:*:*
fedoraproject fedora 35 cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
redhat enterprise_linux 8.0 cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
redhat enterprise_linux_eus 8.6 cpe:2.3:o:redhat:enterprise_linux_eus:8.6:*:*:*:*:*:*:*
redhat enterprise_linux_for_ibm_z_systems 8.0 cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems:8.0:*:*:*:*:*:*:*
redhat enterprise_linux_for_ibm_z_systems_eus 8.6 cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus:8.6:*:*:*:*:*:*:*
redhat enterprise_linux_for_power_little_endian 8.0 cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian:8.0:*:*:*:*:*:*:*
redhat enterprise_linux_for_power_little_endian_eus 8.6 cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:8.6:*:*:*:*:*:*:*
redhat enterprise_linux_server_aus 8.6 cpe:2.3:o:redhat:enterprise_linux_server_aus:8.6:*:*:*:*:*:*:*
redhat enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions 8.6 cpe:2.3:o:redhat:enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions:8.6:*:*:*:*:*:*:*
redhat enterprise_linux_server_tus 8.6 cpe:2.3:o:redhat:enterprise_linux_server_tus:8.6:*:*:*:*:*:*:*
redhat codeready_linux_builder — cpe:2.3:a:redhat:codeready_linux_builder:-:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
splunk universal_forwarder >= 8.2.0, < 8.2.12 cpe:2.3:a:splunk:universal_forwarder:*:*:*:*:*:*:*:*
splunk universal_forwarder >= 9.0.0, < 9.0.6 cpe:2.3:a:splunk:universal_forwarder:*:*:*:*:*:*:*:*
splunk universal_forwarder 9.1.0 cpe:2.3:a:splunk:universal_forwarder:9.1.0:*:*:*:*:*:*:*

References for CVE-2021-31566

cvelogic Threat Intelligence