CVE-2026-59903
Netty: Cache Poisoning and Information Disclosure via CORS Vary Header Overwrite
CVSS Score
6.5
EPSS Score
0.0%
EPSS Percentile
0th
Netty is an asynchronous, event-driven network application framework. Prior to 4.1.137.Final and 4.2.17.Final, io.netty.handler.codec.http.cors.CorsHandler setVaryHeader replaces application Vary headers such as Authorization or Cookie with Origin, allowing a caching proxy or CDN to reuse authenticated responses across users and disclose sensitive information. This issue is fixed in versions 4.1.137.Final and 4.2.17.Final.
| CWE | CWE-524 |
| Vendor | netty |
| Product | netty |
| Published | Aug 17, 2026 |
| Last Updated | Aug 17, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
Low
Availability
None
Affected Versions
netty / netty
< 4.1.137.Final >= 4.2.0.Final, < 4.2.17.Final
References
github.com: https://github.com/netty/netty/security/advisories/GHSA-8c42-7qj2-3j46 github.com: https://github.com/netty/netty/pull/17213 github.com: https://github.com/netty/netty/pull/17217 github.com: https://github.com/netty/netty/releases/tag/netty-4.1.137.Final github.com: https://github.com/netty/netty/releases/tag/netty-4.2.17.Final