$ cve CVE-2021-32708 JSON

CVE-2021-32708

9.8

CRITICAL · CVSS 3.1 · EPSS 3.5% (pctl 89)

In your normal cycle

Critical by CVSS (9.8), but no sign of active exploitation.

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.

Scoring

CVSS	9.8 (CRITICAL, v3.1)
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS	3.49% — more likely to be exploited than 89% of all CVEs
Weakness	CWE-367
On CISA KEV	no
Public exploit	none known
Published	2021-06-24
Last modified	2026-06-17

Affected (2)

Vendor	Product
fedoraproject	fedora
thephpleague	flysystem

References

→ the Explorer · watch your stack · NVD