CVE-2021-32708
CRITICALEPSS 88th pctlDescription
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.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploit Intelligence
Elevated risk: more likely to be exploited than 88% of all known CVEs.
References
Related Vulnerabilities
Other CWE-367 (TOCTOU Race Condition) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2022-36980 | High | 8.1 | 83% | - | Fix |
| CVE-2024-30088 | High | 7.0 | 68% | KEV + Ransom | Fix |
| CVE-2004-0594 | Medium | 5.1 | 55% | - | Fix |
| CVE-2024-50379 | Critical | 9.8 | 44% | - | Fix |
| CVE-2023-38146 | High | 8.8 | 39% | - | Fix |
| CVE-2024-0132 | Critical | 9.0 | 38% | - | Fix |
Common questions
How do I fix CVE-2021-32708?
Upgrade php-league-flysystem on debian 11 to 1.1.3-4 or later.
Is CVE-2021-32708 being actively exploited?
Not that we know of. CVE-2021-32708 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 3.5% is the estimated probability that it will be exploited in the next 30 days. That is higher than 88% of all scored CVEs.
How severe is CVE-2021-32708?
CVE-2021-32708 has a CVSS v3 base score of 9.8, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2021-32708 affect?
Published advisories record a fix for php-league-flysystem (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2021-32708
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.