#VU124823 Interpretation Conflict in Rack - CVE-2026-26961
Published: April 2, 2026
Vulnerability identifier: #VU124823
Vulnerability risk: Medium
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-26961
CWE-ID: CWE-436
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
Rack
Rack
Software vendor:
Rack
Rack
Description
The vulnerability allows a remote attacker to compromise the target system.
The vulnerability exists due to the "Rack::Multipart::Parser" extracts the "boundary" parameter from multipart/form-data using a greedy regular expression. A remote attacker can bypass upstream filtering of uploaded files or form fields.
Remediation
Install updates from vendor's website.