{"id":"CVE-2026-97689","summary":"urllib3: HTTPResponse.stream()/read_chunked() buffers an unbounded chunk-size line into memory","details":"urllib3 is an HTTP client library for Python. From 1.10.3 until 2.8.0, the HTTPResponse.read_chunked and HTTPResponse.stream methods can allocate unbounded memory because the streaming chunk parser buffers the chunk-size field until newline or EOF without a length bound. The trigger is that a malicious server returns Transfer-Encoding: chunked followed by a very long run of bytes without a newline. The attack mechanism is that a malicious HTTP server sends a very long unterminated chunk-size line. The impact is that unbounded memory allocation can exhaust the client process. This issue is fixed in version 2.8.0.","aliases":["GHSA-vxq7-64xx-v4gw"],"modified":"2026-09-30T03:47:29.081924135Z","published":"2026-09-29T15:36:05.963Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-770"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97689.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97689.json"},{"type":"FIX","url":"https://github.com/urllib3/urllib3/commit/cd770b059b543be29298ea5c52afb0b1b090f5ed"},{"type":"WEB","url":"https://github.com/urllib3/urllib3/releases/tag/2.8.0"},{"type":"ADVISORY","url":"https://github.com/urllib3/urllib3/security/advisories/GHSA-vxq7-64xx-v4gw"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-97689"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/urllib3/urllib3","events":[{"introduced":"0b744993bbe30fe6e3e4e0c93416412d8e598301"},{"fixed":"b1d30ab61fe0db8f11092805e8c5ac43e091064a"}],"database_specific":{"extracted_events":[{"introduced":"1.10.3"},{"fixed":"2.8.0"}],"source":"AFFECTED_FIELD"}}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-97689.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H"}]}