Is CVE-2026-26961 actively exploited?

No active exploitation of CVE-2026-26961 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-26961 be exploited remotely?

Yes. CVE-2026-26961 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-26961?

CVE-2026-26961 has a CVSS score of 3.7 (LOW).

HOME VULNERABILITIESCVE-2026-26961

LOW

CVE-2026-26961

CWE-436Published: April 2, 2026· Updated: Apr 3, 2026

3.7

CVSS v3.1

EPSS:0.03%probability of exploitation in 30 daysPercentile:8.2th

Official Description

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Multipart::Parser extracts the boundary parameter from multipart/form-data using a greedy regular expression. When a Content-Type header contains multiple boundary parameters, Rack selects the last one rather than the first. In deployments where an upstream proxy, WAF, or intermediary interprets the first boundary parameter, this mismatch can allow an attacker to smuggle multipart content past upstream inspection and have Rack parse a different body structure than the intermediary validated. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.

NVD Source

Technical Analysis

CVE-2026-26961 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.