Eclipse Grizzly <5.0.2 HTTP Request Smuggling via Malformed Trailer Header
CVE-2026-12606 Published on July 14, 2026
Eclipse Grizzly in versions before 5.0.2, cannot properly parse the trailer section in malformed trailer header's line, which can be leveraged to perform HTTP request smuggling. Grizzly 5.0.1 supports system properties that enable the behavior that fixes the vulnerability - set org.glassfish.grizzly.http.STRICT_HEADER_NAME_VALIDATION_RFC_9110 and org.glassfish.grizzly.http.STRICT_HEADER_VALUE_VALIDATION_RFC_9110 system properties to "true".
Vulnerability Analysis
CVE-2026-12606 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.
Weakness Type
What is a HTTP Request Smuggling Vulnerability?
When malformed or abnormal HTTP requests are interpreted by one or more entities in the data flow between the user and the web server, such as a proxy or firewall, they can be interpreted inconsistently, allowing the attacker to "smuggle" a request to one device without the other device being aware of it.
CVE-2026-12606 has been classified to as a HTTP Request Smuggling vulnerability or weakness.
Products Associated with CVE-2026-12606
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Affected Versions
Eclipse Foundation Eclipse GlassFish:- Version 4.0.0, <= 4.0.2 is affected.
- Version 5.0.0 and below 5.0.2 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.