CVE-2021-4217: A flaw was found in unzip.
Noroxi assessment
Priority: Monitor (action score 13/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.61% (FIRST EPSS); higher than 50.1% of all records.
- Someone with local access to the system can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
- Fixed version: unzip (Alpine:v3.17) 6.0-r11.
Low priority for now. Upgrade to unzip (Alpine:v3.17) 6.0-r11 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
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
- Aug 24, 2022
- Updated
- Nov 2, 2026
- EPSS
- 0.6% · 50th percentile
- CWE
- CWE-476
Report tools
Action score
13
Low priority for now.
- CVSS
- 13 / 40 · 3.3 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.6%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
Is your version affected? Check itNoroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| unzip project | unzip | cpe:2.3:a:unzip_project:unzip |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
| redhat | enterprise linux | cpe:2.3:o:redhat:enterprise_linux |
Versions reported by the vendor
Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.
n/a unzip
- unzip 6.0affected
Affected versions · NVD (6)
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- fedoraproject fedora35
- redhat enterprise linux6.0
- redhat enterprise linux7.0
- redhat enterprise linux8.0
- redhat enterprise linux9.0
- unzip project unzip6.0
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Alpine:v3.17 | unzip | before 6.0-r11 | 6.0-r11 |
| Debian:12 | unzip | from 0 | — |
Same product
unzip project: all recordsOther highest-scoring records for the same primary product.
- CVE-2018-1000035A heap-based buffer overflow exists in Info-Zip UnZip version <= 6.00 in the processing of password-protected archives that allows an…40Plan
- CVE-2020-36561Path traversal in github.com/yi-ge/unzip36Monitor
- CVE-2014-8141Heap-based buffer overflow in the getZip64Data function in Info-ZIP UnZip 6.0 and earlier allows remote attackers to execute arbitrary code…33Monitor
Published before and after this one in the same product
- ← EarlierCVE-2014-8140Jan 31, 2020 · Heap-based buffer overflow in the test_compr_eb function in Info-ZIP UnZip 6.0 and earlier allows remote attackers to execute arbitrary…33Monitor
- ← EarlierCVE-2022-0529Feb 9, 2022 · A flaw was found in Unzip.23Monitor
- ← EarlierCVE-2022-0530Feb 9, 2022 · A flaw was found in Unzip.23Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| alpine:unzip | 6.0-r11 · Alpine:v3.17 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- No account or password is required.
- A user must open a link or visit a page.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- low · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- Low
Weakness class (CWE)
CWE-476 · NULL Pointer DereferenceCVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log (2)
- SSVC exploitation— → none
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.