CVE-2026-102601

Flysystem: WhitespacePathNormalizer's control-character (CorruptedPathDetected) check is bypassed by malformed UTF-8 in the path, affecting every adapter

LOW
3.5
CVSS Score
Published: September 29, 2026 at 03:26 PM UTC
Updated: September 30, 2026 at 07:38 PM UTC
1 product affected across 1 vendorFlysystem

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Severity
LOW3.5
Exploit prediction
EPSS 0.3%
SSVC
PoC

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 3.35.3
Affected range stops below 3.35.3, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

3.5LOWGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-150

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