CVE-2021-32708

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 3.5%, top 12% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Trending — 3 sources updated this week
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 3%CVSS: 9.8Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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 v3
9.8
EG Score
9.8(medium)
EG Risk
—
EPSS
87.9%
KEV
Not listed

Published

June 24, 2021

Last Modified

November 21, 2024

Advisory Details (6)

Auto-updated Jun 1, 2026
Patch available. Sources: github_commit, github.
generic

[SECURITY] Fedora 34 Update: php-league-flysystem-1.1.4-1.fc34 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NWPTENBYKI2IG47GI4DHAACLNRLTWUR5/
github Patch Available

Time-of-check Time-of-use (TOCTOU) Race Condition in league/flysystem · Advisory · thephpleague/flysystem · GitHub

https://github.com/thephpleague/flysystem/security/advisories/GHSA-9f46-5r25-5wfm
github_commit

commit f3ad69181b8a (thephpleague/flysystem)

Fix landed in thephpleague/flysystem commit f3ad69181b8a — awaiting tagged release

https://github.com/thephpleague/flysystem/commit/f3ad69181b8afed2c9edf7be5a2918144ff4ea32
github_commit Patch Available

commit a3c694de9f7e (thephpleague/flysystem)

Patch available: thephpleague/flysystem 3.0.0 (contains commit a3c694de9f7e)

https://github.com/thephpleague/flysystem/commit/a3c694de9f7e844b76f9d1b61296ebf6e8d89d74
generic

league/flysystem - Packagist.org

https://packagist.org/packages/league/flysystem
generic

[SECURITY] Fedora 33 Update: php-league-flysystem-1.1.4-1.fc33 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RNZSWK4GOMJOOHKLZEOE5AQSLC4DNCRZ/

Affected Packages

(1 across 1 ecosystem)
Packagist(1)
PackageVulnerable rangeFixed inDependents
league/flysystem2.0.0 ... 2.1.0 (10 versions)2.1.1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 14× in last 7d / 44× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-22 22:48 UTCEG score recompute
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Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2021-32708?
CVE-2021-32708 is a critical vulnerability published on June 24, 2021. 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…
When was CVE-2021-32708 disclosed?
CVE-2021-32708 was first published in the National Vulnerability Database on June 24, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-32708 actively exploited?
CVE-2021-32708 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 87.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-32708?
CVE-2021-32708 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2021-32708?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-32708, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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