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CVE-2021-4217

A flaw was found in unzip. The vulnerability occurs due to improper handling of Unicode strings,...

3.3 LowFix available

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.

Attack profile

How easy it is to exploit

Attack vector
Local
Complexity
Low
Privileges needed
None
User interaction
Required

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
Low

Exploit likelihood

0.62%Down 0.9 points since Aug 25, 2022
90%50%10%1%

What each source reports

NVD Score used 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 execution.

Record
CVE-2021-4217
CVSS 3.1
3.3 LowCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Weakness
CWE-476
Updated
2026-11-03
CVE List No score

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.

Record
CVE-2021-4217
Weakness
CWE-476
Updated
2026-11-02
EUVDEUVD-2021-34075 No score

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.

Record
EUVD-2021-34075
Updated
2026-11-03
GitHub AdvisoriesGHSA-9xxw-h585-3vfj 7.8

A flaw was found in unzip. The vulnerability occurs due to improper handling of Unicode strings,...

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.

Record
GHSA-9xxw-h585-3vfj
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness
CWE-476
Updated
2026-11-02
OSVALPINE-CVE-2021-4217 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 execution.

Record
ALPINE-CVE-2021-4217
CVSS 3.1
3.3 LowCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Updated
2026-11-02
OSVAZL-10680 3.3

CVE-2021-4217 affecting package unzip for versions less than 6.0-22

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.

Record
AZL-10680
CVSS 3.1
3.3 LowCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Updated
2026-11-02
Show 11 moreShow less
OSVAZL-35342 3.3

CVE-2021-4217 affecting package unzip for versions less than 6.0-22

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.

Record
AZL-35342
CVSS 3.1
3.3 LowCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Updated
2026-11-02
OSVBELL-CVE-2021-4217 3.3

CVE-2021-4217 does not affect BellSoft software

Record
BELL-CVE-2021-4217
CVSS 3.1
3.3 LowCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Updated
2026-11-02
OSV 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 execution.

Record
CVE-2021-4217
CVSS 3.1
3.3 LowCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Updated
2026-11-02
OSVDEBIAN-CVE-2021-4217 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 execution.

Record
DEBIAN-CVE-2021-4217
CVSS 3.1
3.3 LowCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Updated
2026-11-03
OSVOESA-2022-1902 4.7

unzip security update

UnZip is an extraction utility for archives compressed in .zip format. UnZip will list, test, or extract files from a .zip archive, commonly found on MS-DOS systems. The default behavior (with no options) is to extract all files into the current directory (and subdirectorie below it) from the specified zipfile.

Security Fix(es):

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.(CVE-2021-4217)

Record
OESA-2022-1902
CVSS 3.1
4.7 MediumCVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVROOT-OS-DEBIAN-12-CVE-2021-4217 3.3

CVE-2021-4217 in unzip - Patched by Root

Root has patched CVE-2021-4217 in the unzip package for Root:Debian:12. Multiple fixed versions available.

Record
ROOT-OS-DEBIAN-12-CVE-2021-4217
CVSS 3.1
3.3 LowCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Updated
2026-11-02
OSVUBUNTU-CVE-2021-4217 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 execution.

Record
UBUNTU-CVE-2021-4217
CVSS 3.1
3.3 LowCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Updated
2026-11-02
OSVCLSA-2026-1778131952 No score

unzip: Fix of 3 CVEs

  • CVE-2021-4217: fix null pointer dereference in EF_UNIPATH extra field handling
  • CVE-2022-0529: fix heap-based buffer overflow in wide_to_local_string
  • CVE-2022-0530: fix null pointer dereference on invalid UTF-8 input
Record
CLSA-2026-1778131952
Updated
2026-11-02
OSVMGASA-2022-0371 No score

Updated unzip packages fix security vulnerability

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. (CVE-2021-4217)

Conversion of a wide string to a local string that leads to a heap of out-of-bound write. This flaw allows an attacker to input a specially crafted zip file, leading to a crash or code execution. (CVE-2022-0529, CVE-2022-0530)

Record
MGASA-2022-0371
Updated
2026-11-02
OSVUSN-5673-1 No score

unzip vulnerabilities

It was discovered that unzip did not properly handle unicode strings under certain circumstances. If a user were tricked into opening a specially crafted zip file, an attacker could possibly use this issue to cause unzip to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2021-4217)

It was discovered that unzip did not properly perform bounds checking while converting wide strings to local strings. If a user were tricked into opening a specially crafted zip file, an attacker could possibly use this issue to cause unzip to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2022-0529, CVE-2022-0530)

Record
USN-5673-1
Updated
2026-11-02
OSVUSN-7054-1 No score

unzip vulnerability

It was discovered that unzip did not properly handle unicode strings under certain circumstances. If a user were tricked into opening a specially crafted zip file, an attacker could possibly use this issue to cause unzip to crash, resulting in a denial of service, or possibly execute arbitrary code.

Record
USN-7054-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
unzip
Alpine:v3.17
before 6.0-r11
6.0-r11
unzip
Alpine:v3.18
before 6.0-r11
6.0-r11
unzip
Alpine:v3.19
before 6.0-r11
6.0-r11
unzip
Alpine:v3.20
before 6.0-r11
6.0-r11
unzip
Alpine:v3.21
before 6.0-r11
6.0-r11
unzip
Alpine:v3.22
before 6.0-r11
6.0-r11
unzip
Alpine:v3.23
before 6.0-r11
6.0-r11
unzip
Alpine:v3.24
before 6.0-r11
6.0-r11
unzip
Azure Linux:2
before 6.0-22
6.0-22
unzip
Azure Linux:3
before 6.0-22
6.0-22
Show 16 moreShow less
Affected packages
PackageAffectedFixed
unzip
TuxCare:AlmaLinux:9.2
before 6.0-56.el9_2.tuxcare.els1
6.0-56.el9_2.tuxcare.els1
unzip
Debian:12
All versions, plus listed versions
6.0-286.0-28+deb12u16.0-296.0-306.0-31
None known
unzip
Debian:13
All versions, plus listed versions
6.0-296.0-29+deb13u16.0-306.0-31
None known
unzip
Debian:14
All versions, plus listed versions
6.0-296.0-306.0-31
None known
unzip
Mageia:8
before 6.0-2.1.mga8
6.0-2.1.mga8
unzip
openEuler:20.03-LTS-SP1
before 6.0-47.oe1
6.0-47.oe1
unzip
openEuler:20.03-LTS-SP3
before 6.0-47.oe1
6.0-47.oe1
unzip
openEuler:22.03-LTS
before 6.0-50.oe2203
6.0-50.oe2203
unzip
Root:Debian:12
before 6.0-28+deb12u1.aikido.4
6.0-28+deb12u1.aikido.4
rootio-unzip
Root:Debian:12
before 6.0-28+deb12u1.aikido.4
6.0-28+deb12u1.aikido.4
unzip
Ubuntu:Pro:14.04:LTS
before 6.0-9ubuntu1.6+esm1, plus listed versions
6.0-9ubuntu16.0-9ubuntu1.16.0-9ubuntu1.26.0-9ubuntu1.36.0-9ubuntu1.46.0-9ubuntu1.56.0-9ubuntu1.6
6.0-9ubuntu1.6+esm1
unzip
Ubuntu:Pro:16.04:LTS
before 6.0-20ubuntu1.1+esm1, plus listed versions
6.0-17ubuntu16.0-19ubuntu16.0-19ubuntu26.0-20ubuntu16.0-20ubuntu1.1
6.0-20ubuntu1.1+esm1
unzip
Ubuntu:18.04:LTS
before 6.0-21ubuntu1.2, plus listed versions
6.0-21ubuntu16.0-21ubuntu1.1
6.0-21ubuntu1.2
unzip
Ubuntu:20.04:LTS
before 6.0-25ubuntu1.1, plus listed versions
6.0-25ubuntu1
6.0-25ubuntu1.1
unzip
Ubuntu:22.04:LTS
before 6.0-26ubuntu3.1, plus listed versions
6.0-26ubuntu16.0-26ubuntu26.0-26ubuntu3
6.0-26ubuntu3.1
unzip
Ubuntu:24.04:LTS
before 6.0-28ubuntu4.1, plus listed versions
6.0-28ubuntu16.0-28ubuntu26.0-28ubuntu36.0-28ubuntu4
6.0-28ubuntu4.1

History

History
RecordedChangedSources
aliases, productsEUVD, NVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-4217 is a low vulnerability (CVSS 3.3) in Info-zip Unzip, published August 24, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.62%, the 49th percentile. Fixed in unzip 6.0-r11.

References

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