Advisory details:
gitlab / maven/io.netty/netty-all/CVE-2026-100666
| Advisory ID | gitlab/maven/io.netty/netty-all/CVE-2026-100666 |
| Aliases |
CVE-2026-100666
GHSA-2g6j-r8q9-5hr8 |
| Summary | Inconsistent Interpretation of HTTP Requests Netty's `HttpServerCodec` pairs each outbound response with an inbound request by calling `pollMethod()` once per response, including for 1xx informational responses. If a client pipelines an HTTP/1.1 GET carrying an `Expect: 100-continue` header followed by a HEAD request, the 100 Continue response consumes the queued GET method, so the subsequent 200 OK for the GET is paired with HEAD and its body is dropped, while the following 200 OK for the HEAD request is written with a body. This desynchronizes HTTP parsing on the connection, resulting in response splitting and unsafe connection reuse. The `netty-all` artifact is a shaded jar that embeds the vulnerable `HttpServerCodec` 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 |
| System | Score | Found at |
|---|---|---|
| cvssv3.1 | https://gitlab.com/gitlab-org/advisories-community/-/blob/main/maven/io.netty/netty-all/CVE-2026-100666.yml |
| Reference id | Reference type | URL |
|---|---|---|
| https://github.com/netty/netty/security/advisories/GHSA-2g6j-r8q9-5hr8 | ||
| CVE-2026-100666 | https://nvd.nist.gov/vuln/detail/CVE-2026-100666 |
No EPSS data available for this advisory.
| Patch URL | |
|---|---|
| There are no known patches. | |
| 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.