CVE-2026-91990

Tornado before 6.5.8 Memory Amplification DoS via multipart

HIGH
7.5
CVSS Score
Published: September 15, 2026 at 03:18 PM UTC
Updated: September 16, 2026 at 01:57 PM UTC
1 product affected across 1 vendorTornado

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Severity
HIGH7.5
Exploit prediction
EPSS 0.4%
SSVC
PoC

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 6.5.8
Vendor states this is fixed in 6.5.8 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHVulnCheck
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-770

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