Name: CVE-2026-91990: Allocation of Resources Without Limits or Throttling
Creator: Rapid7
Published: 2026-09-15T00:00:00.000Z
License: https://www.rapid7.com/legal/website-terms-of-use/
Keywords: CVE, CVE-2026-91990, CWE-770, CVSS 7.5, EPSS 0.00424

Tornado before 6.5.8 contains a memory amplification vulnerability in parse_multipart_form_data that splits multipart data before validating the max_parts limit. Attackers can send crafted multipart requests with many parts to create large transient lists, exhausting server memory and causing denial of service.

CVSS Details

CVSS 4.0 Base Score: 8.7 (HIGH)
CVSS 4.0 Vector: (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X)
CVSS 3.1 Base Score: 7.5
CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

Covered by Rapid7

Product	Vendor Advisory	Solution File	Added	Published
Alma_linux	—	Upgrade python3-tornado	Oct 12, 2026	Sep 14, 2026
Amazon_linux_2023	—	Upgrade python-tornado-debugsourceUpgrade python3.13-tornado-debuginfoUpgrade python3.13-tornadoUpgrade python3-tornadoUpgrade python3.13-tornado-docUpgrade python-tornado-docUpgrade python3.13-tornado-debugsourceUpgrade python3-tornado-debuginfo	Oct 13, 2026	Sep 15, 2026
Redhat_linux	—	Upgrade python-tornado-debugsourceUpgrade python3-tornadoUpgrade python3-tornado-debuginfo	Sep 17, 2026	Sep 15, 2026

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CVSS Details

Covered by Rapid7

Prioritise with Active Threat Intelligence