{"id":"CVE-2026-34826","aliases":["GHSA-x8cg-fq8g-mxfx"],"url":"https://o3.security/vulnerability/CVE-2026-34826","summary":"Rack: Unbounded Range Count in get_byte_ranges Enables DoS","details":"Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Utils.get_byte_ranges parses the HTTP Range header without limiting the number of individual byte ranges. Although the existing fix for CVE-2024-26141 rejects ranges whose total byte coverage exceeds the file size, it does not restrict the count of ranges. An attacker can supply many small overlapping ranges such as 0-0,0-0,0-0,... to trigger disproportionate CPU, memory, I/O, and bandwidth consumption per request. This results in a denial of service condition in Rack file-serving paths that process multipart byte range responses. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.","published":"2026-04-02T16:45:53.964Z","modified":"2026-09-10T18:26:50.334427644Z","cvss":{"score":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"RubyGems","name":"rack","fixedVersion":"2.2.23"},{"ecosystem":"RubyGems","name":"rack","fixedVersion":"3.1.21"},{"ecosystem":"RubyGems","name":"rack","fixedVersion":"3.2.6"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34826.json"},{"type":"ADVISORY","url":"https://github.com/rack/rack/security/advisories/GHSA-x8cg-fq8g-mxfx"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-34826"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-10T18:26:50.334427644Z"}}