TornadoWeb Tornado up to 6.5.7 Multipart parse_multipart_form_data denial of service

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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6.3$0-$5k0.00-

Summaryinfo

A vulnerability, which was classified as problematic, was found in TornadoWeb Tornado up to 6.5.7. This vulnerability affects the function parse_multipart_form_data of the component Multipart Handler. Executing a manipulation can lead to denial of service. This vulnerability appears as CVE-2026-91990. The attack may be performed from remote. There is no available exploit. You should upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic was found in TornadoWeb Tornado up to 6.5.7. This vulnerability affects the function parse_multipart_form_data of the component Multipart Handler. The manipulation with an unknown input leads to a denial of service vulnerability. The CWE definition for the vulnerability is CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. As an impact it is known to affect availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-91990 since 09/15/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version 6.5.8 eliminates this vulnerability.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.3

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.5
CNA Vector (VulnCheck): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Denial of service
CWE: CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Tornado 6.5.8

Timelineinfo

09/15/2026 Advisory disclosed
09/15/2026 +0 days CVE reserved
09/15/2026 +0 days VulDB entry created
09/15/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-91990 (🔒)
GCVE (CVE): GCVE-0-2026-91990
GCVE (VulDB): GCVE-100-404308

Entryinfo

Created: 09/15/2026 17:53
Changes: 09/15/2026 17:53 (77)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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