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MEDIUM · 4.8

CVE-2026-26962

Rack is a modular Ruby web server interface. From version 3.2.0 to before version 3.2.6, Rack::Multipart::Parser unfolds folded multipart part headers incorrectly. When a multipart header contains an ...

Vulnerability Description

Rack is a modular Ruby web server interface. From version 3.2.0 to before version 3.2.6, Rack::Multipart::Parser unfolds folded multipart part headers incorrectly. When a multipart header contains an obs-fold sequence, Rack preserves the embedded CRLF in parsed parameter values such as filename or name instead of removing the folded line break during unfolding. As a result, applications that later reuse those parsed values in HTTP response headers may be vulnerable to downstream header injection or response splitting. This issue has been patched in version 3.2.6.

CVSS Score

4.8

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE

Affected Products

VendorProductVersions
RackRack>= 3.2.0, < 3.2.6

Related Weaknesses (CWE)

CWE-93

References

FAQ

What is CVE-2026-26962?

CVE-2026-26962 is a vulnerability with a CVSS score of 4.8 (MEDIUM). Rack is a modular Ruby web server interface. From version 3.2.0 to before version 3.2.6, Rack::Multipart::Parser unfolds folded multipart part headers incorrectly. When a multipart header contains an ...

How severe is CVE-2026-26962?

CVE-2026-26962 has been rated MEDIUM with a CVSS base score of 4.8/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-26962?

Check the references section above for vendor advisories and patch information. Affected products include: Rack Rack.