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Vulnerabilities

Vulnerability · CVE-2026-91990

Tornado before 6.5.8 Memory Amplification DoS via multipart

Published Sep 15, 2026 · catalog updated Sep 15, 2026 · Tornado before 6.5.8 Memory

Check if you run it

No confirmed exploitation is on record for CVE-2026-91990. EPSS is 0.42%. Act only if a listed version of Tornado before 6.5.8 Memory is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Tornado before 6.5.8 Memory).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High8.7
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.42%
Remediation
Advisory link
Affected products
vendor tornadoweb tornado

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor tornadoweb tornadoversion unspecified

How to fix CVE-2026-91990

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-91990. EPSS is 0.42%. Act only if a listed version of Tornado before 6.5.8 Memory is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-770: Allocation of Resources Without Limits or Throttling. EPSS 0.42%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Ubuntu security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Sep 15, 2026 · CVE.org

    Updated

    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.

  2. Oct 22, 2026 · Ubuntu Security Notices

    Detected

    CVE-2026-91990 is listed by USN-8952-1: Tornado vulnerabilities.

Sources

  • CVE.orgVulnerability recordCVE-2026-91990

    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 memor

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-91990

    30-day exploitation probability 0.42%

    first.org
  • Ubuntu Security NoticesVendor advisoryCVE-2026-91990

    It was discovered that Tornado did not properly handle certain HTTP requests and network inputs. An attacker could possibly use these issues to cause a denial of service, expose sensitive information, or bypass access controls. (CVE-2023-54397, CVE-2024-14029, CVE-2026-91990, CVE

    ubuntu.com

References

Freshness

Last verified in this catalog Oct 23, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.