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Advisory details: gitlab / maven/io.netty/netty-all/CVE-2026-93569
Advisory ID gitlab/maven/io.netty/netty-all/CVE-2026-93569
Aliases CVE-2026-93569
GHSA-cg2g-fxr4-mg8m
Summary Inconsistent Interpretation of HTTP Requests A flaw was found in Netty. A remote unauthenticated attacker can exploit a vulnerability in Netty's HTTP/1 to HTTP/2 conversion process. When an HTTP/1 request includes both an absolute-form request-target and a conflicting `Host` header, Netty incorrectly prioritizes the `Host` header for the HTTP/2 `:authority` field, discarding the original request-target authority. This inconsistency can allow an attacker to bypass security controls in Netty-based proxies or gateways, potentially leading to unauthorized access, cache poisoning, or misrouting of requests. The `netty-all` artifact is a shaded jar that embeds the vulnerable `HttpConversionUtil` class up to and including version 4.1.68; from version 4.1.69 onwards it ships no bytecode and is not affected.
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 (2)
CWE-20 Improper Input Validation
CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
System Score Found at
cvssv3.1 https://gitlab.com/gitlab-org/advisories-community/-/blob/main/maven/io.netty/netty-all/CVE-2026-93569.yml
Reference id Reference type URL
https://github.com/netty/netty/security/advisories/GHSA-cg2g-fxr4-mg8m
CVE-2026-93569 https://nvd.nist.gov/vuln/detail/CVE-2026-93569
show_bug.cgi?id=2536962 Bug https://bugzilla.redhat.com/show_bug.cgi?id=2536962
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:L/PR:N/UI:N/S:U/C:L/I:H/A:N Found at https://gitlab.com/gitlab-org/advisories-community/-/blob/main/maven/io.netty/netty-all/CVE-2026-93569.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.