{"cve":"CVE-2026-49855","nvd":{"published":"2026-07-14T21:17:02.437","modified":"2026-10-24T21:10:00.130","status":"Deferred","description":"Tornado is a Python web framework and asynchronous networking library. Prior to 6.5.6, Tornado gzip decompression routines processed limited-size chunks but did not enforce an overall limit on accumulated decompressed chunks, allowing a malicious server accessed by SimpleAsyncHTTPClient or an HTTPServer configured with decompress_request=True to consume effectively unlimited memory. This issue is fixed in version 6.5.6.","cvss_v4":null,"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-409"],"references":["https://github.com/tornadoweb/tornado/commit/ff808b33adc52d89a549376a5e3628e92abbc8ff","https://github.com/tornadoweb/tornado/pull/3626","https://github.com/tornadoweb/tornado/security/advisories/GHSA-mgf9-4vpg-hj56"],"products":[],"source":"nvd","synced_at":"2026-10-25T17:50:06.907763985+00:00"},"epss":{"cve":"CVE-2026-49855","score":0.00572,"percentile":0.47012,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-mgf9-4vpg-hj56","url":"https://osv.dev/vulnerability/GHSA-mgf9-4vpg-hj56","summary":"tornado AsyncHTTPClient accumulates decompressed chunks without size limit (gzip bomb)","modified":"2026-09-10T03:51:09.080081033Z","packages":[{"ecosystem":"PyPI","name":"tornado","purl":"pkg:pypi/tornado","ranges":["<6.5.6"],"fixed":["6.5.6"]}]},{"id":"PYSEC-2026-3389","url":"https://osv.dev/vulnerability/PYSEC-2026-3389","summary":"tornado AsyncHTTPClient accumulates decompressed chunks without size limit (gzip bomb)","modified":"2026-07-13T16:33:26.893507727Z","packages":[{"ecosystem":"PyPI","name":"tornado","purl":"pkg:pypi/tornado","ranges":["<6.5.6"],"fixed":["6.5.6"]}]}],"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."]}