CVE-2021-4217
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.
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
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 Low
CVSS: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 High
CVSS: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 Low
CVSS: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 Low
CVSS: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 Low
CVSS: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 Low
CVSS: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 Low
CVSS: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 Low
CVSS: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 Medium
CVSS: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 Low
CVSS: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 Low
CVSS: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
| Package | Affected | Fixed |
|---|---|---|
unzipAlpine:v3.17 |
before 6.0-r11 | 6.0-r11 |
unzipAlpine:v3.18 |
before 6.0-r11 | 6.0-r11 |
unzipAlpine:v3.19 |
before 6.0-r11 | 6.0-r11 |
unzipAlpine:v3.20 |
before 6.0-r11 | 6.0-r11 |
unzipAlpine:v3.21 |
before 6.0-r11 | 6.0-r11 |
unzipAlpine:v3.22 |
before 6.0-r11 | 6.0-r11 |
unzipAlpine:v3.23 |
before 6.0-r11 | 6.0-r11 |
unzipAlpine:v3.24 |
before 6.0-r11 | 6.0-r11 |
unzipAzure Linux:2 |
before 6.0-22 | 6.0-22 |
unzipAzure Linux:3 |
before 6.0-22 | 6.0-22 |
Show 16 moreShow less
| Package | Affected | Fixed |
|---|---|---|
unzipTuxCare:AlmaLinux:9.2 |
before 6.0-56.el9_2.tuxcare.els1 | 6.0-56.el9_2.tuxcare.els1 |
unzipDebian:12 |
All versions, plus listed versions 6.0-286.0-28+deb12u16.0-296.0-306.0-31 |
None known |
unzipDebian:13 |
All versions, plus listed versions 6.0-296.0-29+deb13u16.0-306.0-31 |
None known |
unzipDebian:14 |
All versions, plus listed versions 6.0-296.0-306.0-31 |
None known |
unzipMageia:8 |
before 6.0-2.1.mga8 | 6.0-2.1.mga8 |
unzipopenEuler:20.03-LTS-SP1 |
before 6.0-47.oe1 | 6.0-47.oe1 |
unzipopenEuler:20.03-LTS-SP3 |
before 6.0-47.oe1 | 6.0-47.oe1 |
unzipopenEuler:22.03-LTS |
before 6.0-50.oe2203 | 6.0-50.oe2203 |
unzipRoot:Debian:12 |
before 6.0-28+deb12u1.aikido.4 | 6.0-28+deb12u1.aikido.4 |
rootio-unzipRoot:Debian:12 |
before 6.0-28+deb12u1.aikido.4 | 6.0-28+deb12u1.aikido.4 |
unzipUbuntu: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 |
unzipUbuntu: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 |
unzipUbuntu:18.04:LTS |
before 6.0-21ubuntu1.2, plus listed versions 6.0-21ubuntu16.0-21ubuntu1.1 |
6.0-21ubuntu1.2 |
unzipUbuntu:20.04:LTS |
before 6.0-25ubuntu1.1, plus listed versions 6.0-25ubuntu1 |
6.0-25ubuntu1.1 |
unzipUbuntu:22.04:LTS |
before 6.0-26ubuntu3.1, plus listed versions 6.0-26ubuntu16.0-26ubuntu26.0-26ubuntu3 |
6.0-26ubuntu3.1 |
unzipUbuntu: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
| Recorded | Changed | Sources |
|---|---|---|
| aliases, products | EUVD, NVD | |
| first indexed | CVE 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
bugs.launchpad.net/ubuntu/+source/unzip/+bug/1957077
bugzilla.redhat.com/show_bug.cgi?id=2044583
access.redhat.com/security/cve/CVE-2021-4217
nvd.nist.gov/vuln/detail/CVE-2021-4217
github.com/advisories/GHSA-9xxw-h585-3vfj
security.alpinelinux.org/vuln/CVE-2021-4217
Show 18 moreShow less
docs.bell-sw.com/security/cves/CVE-2021-4217
errata.tuxcare.com/els_os/almalinux9.2esu/CLSA-2026-1778131952.html
security-tracker.debian.org/tracker/CVE-2021-4217
advisories.mageia.org/MGASA-2022-0371.html
bugs.mageia.org/show_bug.cgi?id=29893
bugzilla.redhat.com/show_bug.cgi?id=2051395
bugzilla.redhat.com/show_bug.cgi?id=2051402
debian.org/security/2022/dsa-5202
debian.org/lts/security/2022/dla-3118
lists.opensuse.org/archives/list/[email protected]/thread/VFUXYMOCMRAV3GMQQKYX6T4L2I23XSQU
ubuntu.com/security/notices/USN-5673-1
openeuler.org/en/security/safety-bulletin/detail.html?id=openEuler-SA-2022-1902
ubuntu.com/security/CVE-2021-4217
cve.org/CVERecord?id=CVE-2021-4217
ubuntu.com/security/notices/USN-7054-1
ubuntu.com/security/CVE-2022-0529
ubuntu.com/security/CVE-2022-0530
launchpad.net/bugs/1957077