{"cve":"CVE-2026-97689","nvd":{"published":"2026-09-29T16:17:18.837","modified":"2026-10-13T20:20:06.950","status":"Analyzed","description":"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.","cvss_v4":{"vector":"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","score":8.9},"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-770"],"references":["https://github.com/urllib3/urllib3/commit/cd770b059b543be29298ea5c52afb0b1b090f5ed","https://github.com/urllib3/urllib3/releases/tag/2.8.0","https://github.com/urllib3/urllib3/security/advisories/GHSA-vxq7-64xx-v4gw"],"products":["python:urllib3"],"source":"nvd","synced_at":"2026-10-19T22:56:48.555445741+00:00"},"epss":{"cve":"CVE-2026-97689","score":0.00335,"percentile":0.26585,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-vxq7-64xx-v4gw","url":"https://osv.dev/vulnerability/GHSA-vxq7-64xx-v4gw","summary":"urllib3: HTTPResponse.stream()/read_chunked() buffers an unbounded chunk-size line into memory","modified":"2026-10-01T17:55:57.514829071Z","packages":[{"ecosystem":"PyPI","name":"urllib3","purl":"pkg:pypi/urllib3","ranges":[">=1.10.3 <2.8.0"],"fixed":["2.8.0"]}]},{"id":"PYSEC-2026-4177","url":"https://osv.dev/vulnerability/PYSEC-2026-4177","summary":"urllib3: HTTPResponse.stream()/read_chunked() buffers an unbounded chunk-size line into memory","modified":"2026-10-01T17:45:18.336090182Z","packages":[{"ecosystem":"PyPI","name":"urllib3","purl":"pkg:pypi/urllib3","ranges":[">=1.10.3 <2.8.0"],"fixed":["2.8.0"]}]}],"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."]}