Vulnerability · Published Jan 26, 2022 · Assigned by GitHub_M
CVE-2021-32842Path Traversal in SharpZipLib
Medium 4.0
In plain English
A medium-severity path traversal in sharpziplib from icsharpcode. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.9% (higher than 60% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| NuGet | sharpziplib | 1.3.3 | GHSA-mm6g-mmq6-53ff |
| Ubuntu:22.04:LTS | mono | no fix listed | UBUNTU-CVE-2021-32842 |
| Ubuntu:24.04:LTS | mono | no fix listed | UBUNTU-CVE-2021-32842 |
| Ubuntu:25.10 | mono | no fix listed | UBUNTU-CVE-2021-32842 |
| Ubuntu:26.04:LTS | mono | no fix listed | UBUNTU-CVE-2021-32842 |
| Ubuntu:26.10 | mono | no fix listed | UBUNTU-CVE-2021-32842 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| icsharpcode | sharpziplib | 1.3.3 – before 1.3.31.0.0 – before 1.0.0* |
Weakness: CWE-22 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
References
- https://securitylab.github.com/advisories/GHSL-2021-125-sharpziplib/ x_refsource_CONFIRM
- https://github.com/icsharpcode/SharpZipLib/releases/tag/v1.3.3 x_refsource_MISC