What is CVE-2026-102601?

CVE-2026-102601 is a low-severity vulnerability in Thephpleague Flysystem, classified under CWE-150. CVSS score: 3.5/10. Published 2026-09-29.

How severe is CVE-2026-102601?

Low severity. CVSS v3 base score is 3.5 out of 10.

Vulnerability in Thephpleague Flysystem

CVE-2026-102601

Flysystem is an open source file storage library for PHP. Prior to 3.35.3, the default WhitespacePathNormalizer in src/WhitespacePathNormalizer.php used by Filesystem across adapters calls preg_match with the u modifier and treats both false and 0 as falsy. A path containing malformed UTF-8 causes PCRE to return false, so paths that also contain control characters bypass CorruptedPathDetected::forPath() in normalizePath(). Filesystem::write() can store such names and Filesystem::listContents() can return the raw ANSI escape sequences, allowing hidden or spoofed terminal file listings when an administrator displays them. This issue is fixed in version 3.35.3.

Published 2026-09-29.

CVSS v3 metric

CVSS v3 base score 3.5 (Low). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Thephpleague Flysystem — versions < 3.35.3

Weakness classification (CWE)

CWE-150

References

Frequently asked questions

What is CVE-2026-102601?: CVE-2026-102601 is a low-severity vulnerability in Thephpleague Flysystem, classified under CWE-150. CVSS score: 3.5/10. Published 2026-09-29.
How severe is CVE-2026-102601?: Low severity. CVSS v3 base score is 3.5 out of 10.