CVE-2026-102601
LOWDescription
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.
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:L/UI:R/S:U/C:N/I:L/A:N
Exploit Intelligence
Low risk: more likely to be exploited than 27% of all known CVEs.
References
Related Vulnerabilities
Other CWE-150 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2017-0899 | Critical | 9.8 | 11% | - | Fix |
| CVE-2025-55754 | Critical | 9.6 | 10% | - | Fix |
| CVE-2021-25310 | High | 8.8 | 4.7% | - | - |
| CVE-2020-6932 | Critical | 10.0 | 3.6% | - | - |
| CVE-2024-28085 | Low | 3.3 | 2.2% | - | Fix |
| CVE-2022-30123 | Critical | 10.0 | 2.0% | - | Fix |
Common questions
How do I fix CVE-2026-102601?
Upgrade php-league-flysystem on debian unstable to 3.36.0-1 or later.
Is CVE-2026-102601 being actively exploited?
Not that we know of. CVE-2026-102601 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.34% is the estimated probability that it will be exploited in the next 30 days. That is higher than 27% of all scored CVEs.
How severe is CVE-2026-102601?
CVE-2026-102601 has a CVSS v3 base score of 3.5, rated low. 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-2026-102601 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-2026-102601
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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 2026-09-30.