CVE-2026-102601
CVE-2026-102601 is a low-severity vulnerability with a CVSS 3.x base score of 3.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-150.
Key facts
- Severity: Low (CVSS 3.x base score 3.5)
- EPSS exploit prediction: 0% (25th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-150
- Published:
- Last modified:
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.
Frequently asked questions
- What is 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.
- How severe is CVE-2026-102601?
- CVE-2026-102601 has a CVSS 3.x base score of 3.5, rated low severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.
- Is CVE-2026-102601 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (25th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-102601?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- When was CVE-2026-102601 published?
- CVE-2026-102601 was published on 2026-09-29 and last updated on 2026-09-30.
References
- https://github.com/thephpleague/flysystem/commit/ef4a9a557d769b5d472c403125716706a0d9cc77
- https://github.com/thephpleague/flysystem/releases/tag/3.35.3
- https://github.com/thephpleague/flysystem/security/advisories/GHSA-cxf4-7mrp-vvpr
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