CVE-2021-4217: A flaw was found in unzip

Routine

LOW 3.3WATCHLISTDOWNGRADEMITIGATEMITIGATE

CVE-2021-4217 is a low-severity flaw (CVSS 3.3) affecting unzip, fedora, enterprise linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Public exploit reference
On your watchlist

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	3.3 (Low)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.6% (top 50%)
CISA exploited list	No
Weakness	CWE-476
Published	2022-08-24
Last modified	2026-06-17

Publisher (CNA): Red Hat, Inc. · Vendor: fedoraproject · redhat · unzip project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2022-08-24 16:15 UTCPublished CVE record published
2026-06-17 04:19 UTCUpdated Record last modified

unzip project unzip DOWNGRADE

Affected: 6.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 6.0

1. Check installed version

apt-cache policy unzip || rpm -q unzip || unzip --version

2. No fixed release: DOWNGRADE to a release before 6.0 (Debian / Ubuntu)

apt-cache madison unzip sudo apt install unzip=<VERSION_BEFORE_6.0> sudo apt-mark hold unzip

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list unzip sudo dnf downgrade unzip-<VERSION_BEFORE_6.0> sudo dnf versionlock add unzip

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

fedoraproject fedora MITIGATE

Affected: 35

Fixed in: no fixed release known

Safe to downgrade to: a release before 35

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

redhat enterprise linux MITIGATE

Affected: 6.0 · 7.0 · 8.0 · 9.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 6.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-4217?

unzip: downgrade or apply the listed mitigation; fedora: mitigate or apply the listed mitigation; enterprise linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-4217 being exploited?

CVE-2021-4217 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-4217 affect?

CVE-2021-4217 affects unzip, fedora, enterprise linux. Severity is low (CVSS 3.3). 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 ex

How urgent is CVE-2021-4217?

Priority 34/100. Public exploit reference; On your watchlist

Related CVEs

CVE-2022-0530 MEDIUM 5.5 DOWNGRADE MITIGATE A flaw was found in Unzip
CVE-2022-0529 MEDIUM 5.5 DOWNGRADE MITIGATE A flaw was found in Unzip
CVE-2020-36561 CRITICAL 9.1 UPGRADE Due to improper path sanitization, archives containing relative file paths can cause files to be written (or o
CVE-2019-13232 LOW 3.3 DOWNGRADE MITIGATE Info-ZIP UnZip 6.0 mishandles the overlapping of files inside a ZIP container, leading to denial of service (r
CVE-2018-18384 MEDIUM 5.5 DOWNGRADE Info-ZIP UnZip 6.0 has a buffer overflow in list.c, when a ZIP archive has a crafted relationship between the

References

← Back to latest CVEs