Vulnerability in Netty
CVE-2026-59903
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.
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N.
Affected products
- Netty — versions < 4.1.137.Final, >= 4.2.0.Final, < 4.2.17.Final
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_CONFIRM)
Frequently asked questions
- What is CVE-2026-59903?
- CVE-2026-59903 is a medium-severity vulnerability in Netty, classified under Use of Cache Containing Sensitive Information. CVSS score: 6.5/10. Published 2026-08-17.
- How severe is CVE-2026-59903?
- Medium severity. CVSS v3 base score is 6.5 out of 10.