HOMEVULNERABILITIESCVE-2021-32842
MEDIUM

CVE-2021-32842

CWE-22Published: January 26, 2022· Updated: Jun 17, 2026

5.3
CVSS v3.1

Official Description

SharpZipLib (or #ziplib) is a Zip, GZip, Tar and BZip2 library. Starting version 1.0.0 and prior to version 1.3.3, a check was added if the destination file is under a destination directory. However, it is not enforced that `_baseDirectory` ends with slash. If the _baseDirectory is not slash terminated like `/home/user/dir` it is possible to create a file with a name thats begins as the destination directory one level up from the directory, i.e. `/home/user/dir.sh`. Because of the file name and destination directory constraints, the arbitrary file creation impact is limited and depends on the use case. Version 1.3.3 fixed this vulnerability.

NVD Source

Technical Analysis

CVE-2021-32842 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityLow
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Affected Vendors & Products

sharpziplib_project1 product(s)
sharpziplib
Source: NVD CPE · 1 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttps://github.com/icsharpcode/SharpZipLib/releases/tag/v1.3.3
ADVISORYhttps://securitylab.github.com/advisories/GHSL-2021-125-sharpziplib/
ADVISORYhttps://github.com/icsharpcode/SharpZipLib/releases/tag/v1.3.3
ADVISORYhttps://securitylab.github.com/advisories/GHSL-2021-125-sharpziplib/

All References (4)

→
https://github.com/icsharpcode/SharpZipLib/releases/tag/v1.3.3Release Notes · Third Party Advisory
→
https://securitylab.github.com/advisories/GHSL-2021-125-sharpziplib/Exploit · Third Party Advisory
→
https://github.com/icsharpcode/SharpZipLib/releases/tag/v1.3.3Release Notes · Third Party Advisory
→
https://securitylab.github.com/advisories/GHSL-2021-125-sharpziplib/Exploit · Third Party Advisory

Quick Facts

CVE IDCVE-2021-32842
CVSS Score5.3 / 10
SeverityMEDIUM
WeaknessCWE-22
CISA KEVNo
Affected1 vendor(s)
PublishedJan 26, 2022

Related CVEs (CWE-22)

CVE-2025-52562
10.0
CVE-2010-5286
10.0
CVE-2025-58321
10.0
CVE-2025-54261
10.0
CVE-2026-59555
10.0
CVE-2011-1565
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-32842 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
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