Vulnerability Description
Flysystem is an open source file storage library for PHP. The whitespace normalisation using in 1.x and 2.x removes any unicode whitespace. Under certain specific conditions this could potentially allow a malicious user to execute code remotely. The conditions are: A user is allowed to supply the path or filename of an uploaded file, the supplied path or filename is not checked against unicode chars, the supplied pathname checked against an extension deny-list, not an allow-list, the supplied path or filename contains a unicode whitespace char in the extension, the uploaded file is stored in a directory that allows PHP code to be executed. Given these conditions are met a user can upload and execute arbitrary code on the system under attack. The unicode whitespace removal has been replaced with a rejection (exception). For 1.x users, upgrade to 1.1.4. For 2.x users, upgrade to 2.1.1.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Thephpleague | Flysystem | >= 1.0.0, < 1.1.4 |
| Fedoraproject | Fedora | 33 |
Related Weaknesses (CWE)
References
- https://github.com/thephpleague/flysystem/commit/a3c694de9f7e844b76f9d1b61296ebfPatchThird Party Advisory
- https://github.com/thephpleague/flysystem/commit/f3ad69181b8afed2c9edf7be5a29181PatchThird Party Advisory
- https://github.com/thephpleague/flysystem/security/advisories/GHSA-9f46-5r25-5wfPatchThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://packagist.org/packages/league/flysystemProductThird Party Advisory
- https://github.com/thephpleague/flysystem/commit/a3c694de9f7e844b76f9d1b61296ebfPatchThird Party Advisory
- https://github.com/thephpleague/flysystem/commit/f3ad69181b8afed2c9edf7be5a29181PatchThird Party Advisory
- https://github.com/thephpleague/flysystem/security/advisories/GHSA-9f46-5r25-5wfPatchThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://packagist.org/packages/league/flysystemProductThird Party Advisory
FAQ
What is CVE-2021-32708?
CVE-2021-32708 is a vulnerability with a CVSS score of 9.8 (CRITICAL). Flysystem is an open source file storage library for PHP. The whitespace normalisation using in 1.x and 2.x removes any unicode whitespace. Under certain specific conditions this could potentially all...
How severe is CVE-2021-32708?
CVE-2021-32708 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2021-32708?
Check the references section above for vendor advisories and patch information. Affected products include: Thephpleague Flysystem, Fedoraproject Fedora.