{"id":54284,"date":"2026-05-13T15:10:39","date_gmt":"2026-05-13T15:10:39","guid":{"rendered":"https:\/\/zero.redgem.net\/?p=54284"},"modified":"2026-05-13T15:10:39","modified_gmt":"2026-05-13T15:10:39","slug":"netty-httpcontentdecompressor-maxallocation-bypass-via-content-encoding-brzstdsnappy-enables-decompr","status":"publish","type":"post","link":"https:\/\/zero.redgem.net\/?p=54284","title":{"rendered":"Netty: HttpContentDecompressor maxAllocation bypass via Content-Encoding: br\/zstd\/snappy enables decompression bomb DoS_CVE-2026-42587"},"content":{"rendered":"<p>{&#8220;lastseen&#8221;:&#8221;&#8221;,&#8221;description&#8221;:&#8221;Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpContentDecompressor accepts a maxAllocation parameter to limit decompression buffer size and prevent decompression bomb attacks. This limit is correctly enforced for gzip and deflate encodings via ZlibDecoder, but is silently ignored when the content encoding is br (Brotli), zstd, or snappy. An attacker can bypass the configured decompression limit by sending a compressed payload with Content-Encoding: br instead of Content-Encoding: gzip, causing unbounded memory allocation and out-of-memory denial of service. The same vulnerability exists in DelegatingDecompressorFrameListener for HTTP\/2 connections. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.&#8221;,&#8221;published&#8221;:&#8221;2026-05-13T18:22:21.699Z&#8221;,&#8221;modified&#8221;:&#8221;2026-05-13T18:44:09.298Z&#8221;,&#8221;type&#8221;:&#8221;cve&#8221;,&#8221;title&#8221;:&#8221;Netty: HttpContentDecompressor maxAllocation bypass via Content-Encoding: br\/zstd\/snappy enables decompression bomb DoS&#8221;,&#8221;source&#8221;:&#8221;GitHub_M&#8221;,&#8221;references&#8221;:&#8221;https:\/\/github.com\/netty\/netty\/security\/advisories\/GHSA-f6hv-jmp6-3vwv&#8221;,&#8221;id&#8221;:&#8221;CVE-2026-42587&#8243;,&#8221;bulletinFamily&#8221;:&#8221;&#8221;,&#8221;cwe&#8221;:[&#8220;CWE-400&#8243;],&#8221;cvelist&#8221;:null,&#8221;sourceData&#8221;:&#8221;netty netty \\u003e= 4.2.0.Alpha1, \\u003c 4.2.13.Final\\nnetty netty \\u003c 4.1.133.Final\\nio.netty netty-codec-http \\u003e= 4.2.0.Alpha1, \\u003c 4.2.13.Final\\nio.netty netty-codec-http \\u003c 4.1.133.Final\\nio.netty netty-codec-http2 \\u003e= 4.2.0.Alpha1, \\u003c 4.2.13.Final\\nio.netty netty-codec-http2 \\u003c 4.1.133.Final&#8221;,&#8221;sourceHref&#8221;:&#8221;&#8221;,&#8221;cvss&#8221;:{&#8220;score&#8221;:7.5,&#8221;severity&#8221;:&#8221;HIGH&#8221;,&#8221;vector&#8221;:&#8221;CVSS:3.1\/AV:N\/AC:L\/PR:N\/UI:N\/S:U\/C:N\/I:N\/A:H&#8221;,&#8221;version&#8221;:&#8221;3.1&#8243;},&#8221;cvss2&#8243;:{},&#8221;cvss3&#8243;:{&#8220;version&#8221;:&#8221;&#8221;,&#8221;vectorString&#8221;:&#8221;&#8221;,&#8221;baseScore&#8221;:0,&#8221;baseSeverity&#8221;:&#8221;&#8221;,&#8221;attackVector&#8221;:&#8221;&#8221;,&#8221;attackComplexity&#8221;:&#8221;&#8221;,&#8221;privilegesRequired&#8221;:&#8221;&#8221;,&#8221;userInteraction&#8221;:&#8221;&#8221;,&#8221;scope&#8221;:&#8221;&#8221;,&#8221;confidentialityImpact&#8221;:&#8221;&#8221;,&#8221;integrityImpact&#8221;:&#8221;&#8221;,&#8221;availabilityImpact&#8221;:&#8221;&#8221;,&#8221;cvssV3&#8243;:{&#8220;version&#8221;:&#8221;&#8221;,&#8221;vectorString&#8221;:&#8221;&#8221;,&#8221;baseScore&#8221;:0,&#8221;baseSeverity&#8221;:&#8221;&#8221;,&#8221;attackVector&#8221;:&#8221;&#8221;,&#8221;attackComplexity&#8221;:&#8221;&#8221;,&#8221;privilegesRequired&#8221;:&#8221;&#8221;,&#8221;userInteraction&#8221;:&#8221;&#8221;,&#8221;scope&#8221;:&#8221;&#8221;,&#8221;confidentialityImpact&#8221;:&#8221;&#8221;,&#8221;integrityImpact&#8221;:&#8221;&#8221;,&#8221;availabilityImpact&#8221;:&#8221;&#8221;}},&#8221;href&#8221;:&#8221;&#8221;,&#8221;category_name&#8221;:&#8221;CVE&#8221;,&#8221;post_link&#8221;:&#8221;&#8221;,&#8221;product&#8221;:&#8221;netty&#8221;,&#8221;version&#8221;:&#8221;\\u003e= 4.2.0.Alpha1, \\u003c 4.2.13.Final&#8221;,&#8221;vendor&#8221;:&#8221;netty&#8221;,&#8221;ai_description&#8221;:&#8221;&#8221;,&#8221;ai_severity&#8221;:&#8221;&#8221;,&#8221;ai_vendor&#8221;:&#8221;&#8221;,&#8221;ai_product&#8221;:&#8221;&#8221;,&#8221;ai_version&#8221;:&#8221;&#8221;,&#8221;ai_score&#8221;:0}<\/p>\n","protected":false},"excerpt":{"rendered":"<p>{&#8220;lastseen&#8221;:&#8221;&#8221;,&#8221;description&#8221;:&#8221;Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpContentDecompressor accepts a maxAllocation parameter to limit decompression buffer size and prevent&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[6,8,16,12,15,13,7,11,5],"class_list":["post-54284","post","type-post","status-publish","format-standard","hentry","category-category_cve","tag-cve","tag-cvss","tag-cvss-75","tag-exploit","tag-high","tag-news","tag-security","tag-tapic","tag-vulnerability"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.5 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Netty: HttpContentDecompressor maxAllocation bypass via Content-Encoding: br\/zstd\/snappy enables decompression bomb DoS_CVE-2026-42587 - zero redgem<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/zero.redgem.net\/?p=54284\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Netty: HttpContentDecompressor maxAllocation bypass via Content-Encoding: br\/zstd\/snappy enables decompression bomb DoS_CVE-2026-42587 - zero redgem\" \/>\n<meta property=\"og:description\" content=\"{&#8220;lastseen&#8221;:&#8221;&#8221;,&#8221;description&#8221;:&#8221;Netty is an asynchronous, event-driven network application framework. 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