CVE-2021-32708
What it is
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.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 3.5% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 3.5% in the next 30 days (EPSS).
- Severity: 9.8 CRITICAL (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 3.5% · EPSS, next 30 days
- Weakness
- CWE-367
- Record status
- Modified
Affected
- Thephpleague Flysystem < 1.1.4
- Thephpleague Flysystem < 2.1.1
- Fedoraproject Fedora 33
- Fedoraproject Fedora 34
Attack profile CVSS 3.1 · 9.8
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2021-32708.md and follow it. Check whether this project is affected by CVE-2021-32708. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://github.com/thephpleague/flysystem/commit/a3c694de9f7e844b76f9d1b61296ebf6e8d89d74
- https://github.com/thephpleague/flysystem/commit/f3ad69181b8afed2c9edf7be5a2918144ff4ea32
- https://github.com/thephpleague/flysystem/security/advisories/GHSA-9f46-5r25-5wfm
- https://github.com/thephpleague/flysystem/commit/a3c694de9f7e844b76f9d1b61296ebf6e8d89d74
- https://github.com/thephpleague/flysystem/commit/f3ad69181b8afed2c9edf7be5a2918144ff4ea32
- https://github.com/thephpleague/flysystem/security/advisories/GHSA-9f46-5r25-5wfm
References
- https://github.com/thephpleague/flysystem/commit/a3c694de9f7e844b76f9d1b61296ebf6e8d89d74
- https://github.com/thephpleague/flysystem/commit/f3ad69181b8afed2c9edf7be5a2918144ff4ea32
- https://github.com/thephpleague/flysystem/security/advisories/GHSA-9f46-5r25-5wfm
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NWPTENBYKI2IG47GI4DHAACLNRLTWUR5/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RNZSWK4GOMJOOHKLZEOE5AQSLC4DNCRZ/
- https://packagist.org/packages/league/flysystem
- https://github.com/thephpleague/flysystem/commit/a3c694de9f7e844b76f9d1b61296ebf6e8d89d74
- https://github.com/thephpleague/flysystem/commit/f3ad69181b8afed2c9edf7be5a2918144ff4ea32
- https://github.com/thephpleague/flysystem/security/advisories/GHSA-9f46-5r25-5wfm
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NWPTENBYKI2IG47GI4DHAACLNRLTWUR5/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RNZSWK4GOMJOOHKLZEOE5AQSLC4DNCRZ/
- https://packagist.org/packages/league/flysystem