{"cve":"CVE-2026-42587","nvd":{"published":"2026-05-13T19:17:24.460","modified":"2026-10-26T17:10:03.270","status":"Modified","description":"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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-400","CWE-770"],"references":["https://github.com/netty/netty/security/advisories/GHSA-f6hv-jmp6-3vwv","https://access.redhat.com/errata/RHSA-2026:23808","https://access.redhat.com/errata/RHSA-2026:24502","https://access.redhat.com/errata/RHSA-2026:25123","https://access.redhat.com/errata/RHSA-2026:28010"],"products":["netty:netty"],"source":"nvd","synced_at":"2026-10-26T17:39:09.812804557+00:00"},"epss":{"cve":"CVE-2026-42587","score":0.0099,"percentile":0.6228,"date":"2026-10-26"},"kev":null,"osv":[{"id":"GHSA-f6hv-jmp6-3vwv","url":"https://osv.dev/vulnerability/GHSA-f6hv-jmp6-3vwv","summary":"Netty: HttpContentDecompressor maxAllocation bypass when Content-Encoding set to br/zstd/snappy leads to decompression bomb DoS","modified":"2026-09-10T03:51:05.447415711Z","packages":[{"ecosystem":"Maven","name":"io.netty:netty-codec-http","purl":"pkg:maven/io.netty/netty-codec-http","ranges":[">=4.2.0.Alpha1 <4.2.13.Final"],"fixed":["4.2.13.Final"]},{"ecosystem":"Maven","name":"io.netty:netty-codec-http2","purl":"pkg:maven/io.netty/netty-codec-http2","ranges":[">=4.2.0.Alpha1 <4.2.13.Final"],"fixed":["4.2.13.Final"]},{"ecosystem":"Maven","name":"io.netty:netty-codec-http","purl":"pkg:maven/io.netty/netty-codec-http","ranges":["<4.1.133.Final"],"fixed":["4.1.133.Final"]},{"ecosystem":"Maven","name":"io.netty:netty-codec-http2","purl":"pkg:maven/io.netty/netty-codec-http2","ranges":["<4.1.133.Final"],"fixed":["4.1.133.Final"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}