{"id":"CVE-2026-73507","aliases":["GHSA-v74w-7mr3-4qg3"],"url":"https://o3.security/vulnerability/CVE-2026-73507","summary":"Netty: Denial of Service in XmlFrameDecoder via CPU Exhaustion","details":"### Summary\nAn attacker can cause Denial of Service by sending a specially crafted malicious XML payload (e.g., repeated `</` characters) to a Netty server utilizing XmlFrameDecoder, causing the server's EventLoop thread to exhaust CPU resources and become unresponsive.\n\n### Details\n`io.netty.handler.codec.xml.XmlFrameDecoder` suffers from a vulnerability resulting in CPU exhaustion. When `<` followed by `/` is encountered, the decoder scans the remaining buffer for a closing `>`.\nBecause the parser state is not saved between `decode()` invocations, an attacker can trickle-feed a payload of `</` characters. This forces the decoder to repeatedly rescan the entire accumulated buffer. A 1MB `maxFrameLength` is enough to completely hang a server's thread while it loops endlessly.\n\n### Impact\nDenial of Service via CPU Exhaustion. Any application utilizing Netty's XmlFrameDecoder is impacted. An unauthenticated remote attacker can exploit this flaw by sending a modest amount of malformed XML data to an exposed port.","published":"2026-08-13T14:25:34.073Z","modified":"2026-09-25T08:21:43.895453Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":{"score":0.00455,"percentile":0.38644,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Maven","name":"io.netty:netty-codec-xml","fixedVersion":"4.2.16.Final"},{"ecosystem":"Maven","name":"io.netty:netty-codec-xml","fixedVersion":"4.1.136.Final"}],"fix":{"url":"https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b","label":"netty/netty@5b68c61"},"references":[{"type":"WEB","url":"https://github.com/netty/netty/releases/tag/netty-4.1.136.Final"},{"type":"WEB","url":"https://github.com/netty/netty/releases/tag/netty-4.2.16.Final"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73507.json"},{"type":"ADVISORY","url":"https://github.com/netty/netty/security/advisories/GHSA-v74w-7mr3-4qg3"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-73507"},{"type":"FIX","url":"https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b"},{"type":"FIX","url":"https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6"},{"type":"WEB","url":"https://github.com/netty/netty/pull/17063"},{"type":"WEB","url":"https://github.com/netty/netty/pull/17065"},{"type":"PACKAGE","url":"https://github.com/netty/netty"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-25T08:21:43.895453Z"}}