CVE-2021-4217

Exp

A flaw was found in unzip. The vulnerability occurs due to improper handling of Unicode strings, which can lead to a null pointer dereference. This flaw allows an attacker to input a specially crafted zip file, leading to a crash or code execution.

Published: 2022-08-24 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-4217 is rated Exploit Available (50/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.17%). 2 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

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

Public exploit references (Exploit-DB) for CVE-2021-4217

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-4217

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 2025-11-21 0.37% 0.17% -0.20%
2 2025-11-18 0.17% 0.37% +0.20%
3 2025-09-11 — 0.17% —

Full EPSS history (9 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-4217

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
3.3 3.1 LOW
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L 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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 1.8 1.4 [email protected]

Weakness enumeration for CVE-2021-4217

OS Trackers for CVE-2021-4217

vendor priority summary link
alpine high CVE-2021-4217: 1 source package rows (unzip); 40 state rows across 8 repos (3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, 3.23-main, edge-main); fixed 18, open 22. https://security.alpinelinux.org/vuln/CVE-2021-4217
debian unimportant CVE-2021-4217 unimportant priority: Debian including 1 source packages (unzip), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 5. https://security-tracker.debian.org/tracker/CVE-2021-4217
redhat low — https://access.redhat.com/security/cve/CVE-2021-4217
suse medium CVE-2021-4217 severity moderate: SUSE including 3 source package names (unzip, unzip-5.52-142.34.11.1, unzip-6.00-11.18.11.1), 42 product×package rows across 42 product lines (HPE Helion OpenStack 8, SUSE CaaS Platform 4.0, … (42 product lines)): Known Not Affected 40, Fixed 2. https://www.suse.com/security/cve/CVE-2021-4217/
ubuntu low CVE-2021-4217 low priority: Ubuntu including 1 source packages (unzip), 11 status rows across 11 suites (bionic, focal, impish, jammy, kinetic, lunar, mantic, noble, trusty, upstream, xenial): released 6, ignored 4, needs-triage 1. https://ubuntu.com/security/CVE-2021-4217

Affected software / configurations for CVE-2021-4217

Vendor Product Version Raw CPE
unzip_project unzip 6.0 cpe:2.3:a:unzip_project:unzip:6.0:*:*:*:*:*:*:*
fedoraproject fedora 35 cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
redhat enterprise_linux 6.0 cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:*
redhat enterprise_linux 7.0 cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
redhat enterprise_linux 8.0 cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
redhat enterprise_linux 9.0 cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*

References for CVE-2021-4217

URL Tags
https://access.redhat.com/security/cve/CVE-2021-4217 Third Party Advisory
https://bugs.launchpad.net/ubuntu/+source/unzip/+bug/1957077 Exploit Issue Tracking Patch Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2044583 Exploit Issue Tracking Third Party Advisory
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