CVE-2026-42549

CVE-2026-42549 is a medium-severity vulnerability with a CVSS 3.x base score of 4.4. 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-22.

Key facts

Description

Flight is an extensible micro-framework for PHP. Prior to 3.18.1, the make:controller CLI command calls mkdir(..., recursive: true) on a path built from the user-supplied controller name, before Nette's class-name validation runs. The class-file write is correctly rejected by Nette when the name contains /, but the recursive directory creation side effect is already committed — including directories located outside the project root through ../ traversal. This vulnerability is fixed in 3.18.1.

Frequently asked questions

What is CVE-2026-42549?
Flight is an extensible micro-framework for PHP. Prior to 3.18.1, the make:controller CLI command calls mkdir(..., recursive: true) on a path built from the user-supplied controller name, before Nette's class-name validation runs. The class-file write is correctly rejected by Nette when the name contains /, but the recursive directory creation side effect is already committed — including directories located outside the project root through ../ traversal. This vulnerability is fixed in 3.18.1.
How severe is CVE-2026-42549?
CVE-2026-42549 has a CVSS 3.x base score of 4.4, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability low.
Is CVE-2026-42549 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (5th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-42549?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-42549 have an EU (EUVD) identifier?
Yes. CVE-2026-42549 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30148.
When was CVE-2026-42549 published?
CVE-2026-42549 was published on 2026-05-13 and last updated on 2026-06-17.

References

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