{"id":"CVE-2026-79658","title":"Ech0 before 5.0.1 does not impose any size or shape limit on the Accept-Language header processed by its i18n middleware, which runs on every HTTP request","summary":"Ech0 before 5.0.1 does not impose any size or shape limit on the Accept-Language header processed by its i18n middleware, which runs on every HTTP request. The header is passed unfiltered to go-i18n's NewLocalizer, which internally calls…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-400"],"published":"2026-08-25","updated":"2026-08-29","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-79658","references":[{"url":"https://github.com/lin-snow/Ech0/security/advisories/GHSA-mqxv-9rm6-w8qc","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/ech0-before-denial-of-service-via-accept-language","label":"disclosure@vulncheck.com"}],"tags":["nvd"],"epss":0.00291,"epssPercentile":0.21921,"ingestedAt":"2026-08-29T21:42:33.404Z","slug":"CVE-2026-79658","body":"## Overview\n\nEch0 before 5.0.1 does not impose any size or shape limit on the Accept-Language header processed by its i18n middleware, which runs on every HTTP request. The header is passed unfiltered to go-i18n's NewLocalizer, which internally calls golang.org/x/text/language.ParseAcceptLanguage. The CVE-2022-32149 mitigation in x/text caps '-' characters but not '_' characters, which the parser aliases to '-', allowing quadratic-time parsing to be triggered with a large header (up to Go's default 1 MiB) built from underscore separators. An unauthenticated attacker can send such requests to consume roughly 1.5 seconds of CPU each, and concurrent requests can saturate a multi-core server (denial of service).\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}