Staging Environment: Content and features may be unstable or change without notice.
Advisory details: gitlab / maven/io.netty/netty-codec-http/CVE-2026-59903
Advisory ID gitlab/maven/io.netty/netty-codec-http/CVE-2026-59903
Aliases CVE-2026-59903
GHSA-8c42-7qj2-3j46
Summary Netty Vulnerable to Cache Poisoning and Information Disclosure via CORS Vary Header Overwrite Netty's `CorsHandler` silently overwrites existing `Vary` headers, enabling cache poisoning and sensitive information disclosure.
Status Published
Exploitability 0.5
Weighted Severity 0.0
Risk
Affected and Fixed Packages Package Details
Introduced and Fixed Package Commit Patches Package Commit Patches Details
Weaknesses (3)
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
CWE-524 Use of Cache Containing Sensitive Information
System Score Found at
cvssv3.1 https://gitlab.com/gitlab-org/advisories-community/-/blob/main/maven/io.netty/netty-codec-http/CVE-2026-59903.yml
Reference id Reference type URL
https://github.com/netty/netty/pull/17213
https://github.com/netty/netty/pull/17217
https://github.com/netty/netty/releases/tag/netty-4.1.137.Final
https://github.com/netty/netty/releases/tag/netty-4.2.17.Final
https://github.com/netty/netty/security/advisories/GHSA-8c42-7qj2-3j46
CVE-2026-59903 https://nvd.nist.gov/vuln/detail/CVE-2026-59903
GHSA-8c42-7qj2-3j46 https://github.com/advisories/GHSA-8c42-7qj2-3j46
No exploits are available.

No EPSS data available for this advisory.

Patch URL
There are no known patches.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N Found at https://gitlab.com/gitlab-org/advisories-community/-/blob/main/maven/io.netty/netty-codec-http/CVE-2026-59903.yml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none

There are no SSVC decisions available.