CVE-2020-21674

Heap-based buffer overflow in archive_string_append_from_wcs() (archive_string.c) in libarchive-3.4.1dev allows remote attackers to cause a denial of service (out-of-bounds write in heap memory resulting into a crash) via a crafted archive file. NOTE: this only affects users who downloaded the development code from GitHub. Users of the product's official releases are unaffected.

Published: 2020-10-15 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-21674 is rated Moderate Risk (54/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 2.06%). 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-2020-21674

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 1.65% 2.06% +0.40%
2 2025-11-21 0.48% 1.65% +1.18%
3 2025-11-18 — 0.48% —

Full EPSS history (14 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-21674

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 3.6 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2020-21674

OS Trackers for CVE-2020-21674

vendor priority summary link
debian unimportant CVE-2020-21674 unimportant 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-2020-21674
redhat medium — https://access.redhat.com/security/cve/CVE-2020-21674
suse medium CVE-2020-21674 severity moderate: SUSE including 4 source package names (bsdtar, libarchive, libarchive-devel, libarchive13), 68 product×package rows across 35 product lines (HPE Helion OpenStack 8, SUSE Enterprise Storage 5, … (35 product lines)): Known Not Affected 68. https://www.suse.com/security/cve/CVE-2020-21674/
ubuntu medium CVE-2020-21674 medium priority: Ubuntu including 1 source packages (libarchive), 5 status rows across 5 suites (bionic, focal, trusty, upstream, xenial): not-affected 4, needs-triage 1. https://ubuntu.com/security/CVE-2020-21674

Affected software / configurations for CVE-2020-21674

Vendor Product Version Raw CPE
libarchive libarchive 3.4.1 cpe:2.3:a:libarchive:libarchive:3.4.1:*:*:*:*:*:*:*

References for CVE-2020-21674

cvelogic Threat Intelligence