CVE-2026-12606Network attack vector

HTTP request smuggling via malformed trailer parsing

Published Jul 14, 2026 · Updated Jul 14, 2026

HTTP request smuggling in Eclipse GlassFish's Grizzly parser before 5.0.2 allows remote attackers to inject requests via malformed trailers. The trailer parser accepts malformed header lines without strict RFC 9110 name and value validation, so intermediaries and Grizzly can disagree on request boundaries. Exploitation requires an HTTP intermediary that parses the trailer differently; a smuggled request can alter backend request processing.

CVSS severity6.3
Medium
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

HTTP request smuggling in Eclipse GlassFish's Grizzly parser before 5.0.2 allows remote attackers to inject requests via malformed trailers. The trailer parser accepts malformed header lines without strict RFC 9110 name and value validation, so intermediaries and Grizzly can disagree on request boundaries. Exploitation requires an HTTP intermediary that parses the trailer differently; a smuggled request can alter backend request processing.

The record

CVE
CVE-2026-12606
Published
Jul 14, 2026
Updated
Jul 14, 2026
Vendor
The Eclipse Foundation
Product
Eclipse GlassFish
Classifications
CWE-444, CAPEC-33, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.0.0 <=4.0.2
  2. Affected versionversion=5.0.0 <5.0.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Eclipse Foundation · Eclipse GlassFishversion=4.0.0 <=4.0.2; version=5.0.0 <5.0.2

Published CVSS scores

6.3Eclipse FoundationCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-444Inconsistent Interpretation of HTTP Requests
CAPEC-33HTTP Request Smuggling
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo