{"id":"CVE-2026-42304","summary":"Twisted: Denial of Service (DoS) in twisted.names via Crafted DNS Compression Pointer Chains","details":"Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.4.0rc2, the twisted.names module is vulnerable to a Denial of Service (DoS) attack via resource exhaustion during DNS name decompression. A remote, unauthenticated attacker can exploit this by sending a crafted TCP DNS packet containing deeply chained compression pointers. This flaw bypasses previous loop-prevention logic, causing the single-threaded Twisted reactor to hang while processing millions of recursive lookups, effectively freezing the server. This vulnerability is fixed in 26.4.0rc2.","aliases":["GHSA-grgv-6hw6-v9g4","PYSEC-2026-160"],"modified":"2026-06-18T03:57:01.556353528Z","published":"2026-05-13T20:20:29.149Z","related":["CGA-fg78-f8xv-6cr2","SUSE-SU-2026:22004-1","SUSE-SU-2026:2218-1","SUSE-SU-2026:2219-1","openSUSE-SU-2026:10759-1","openSUSE-SU-2026:20862-1"],"database_specific":{"cwe_ids":["CWE-400","CWE-407"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42304.json","cna_assigner":"GitHub_M"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42304.json"},{"type":"ADVISORY","url":"https://github.com/twisted/twisted/security/advisories/GHSA-grgv-6hw6-v9g4"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42304"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/twisted/twisted","events":[{"introduced":"0"},{"fixed":"3dc92b79333c231338390c2b8cec5c142a31863d"}],"database_specific":{"cpe":["cpe:2.3:a:twisted:twisted:*:*:*:*:*:*:*:*","cpe:2.3:a:twisted:twisted:26.4.0:rc1:*:*:*:*:*:*"],"extracted_events":[{"introduced":"0"},{"fixed":"26.4.0"},{"last_affected":"26.4.0-rc1"}],"source":["CPE_RANGE","CPE_STRING"]}}],"versions":["twisted-26.4.0rc2","twisted-26.4.0rc1","before-black"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-42304.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}