CVE-2026-91990
Publication date 15 September 2026
Last updated 22 October 2026
Ubuntu priority
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| python-tornado | 26.10 stonking |
Fixed in 6.5.5-5ubuntu1
|
| 26.04 LTS resolute |
Fixed in 6.5.4-0.1ubuntu0.2
|
|
| 24.04 LTS noble |
Fixed in 6.4.0-1ubuntu0.6
|
|
| 22.04 LTS jammy |
Fixed in 6.1.0-3ubuntu0.1~esm6
|
|
| 20.04 LTS focal |
Fixed in 6.0.3+really5.1.1-3ubuntu0.1~esm6
|
|
| 18.04 LTS bionic |
Fixed in 4.5.3-1ubuntu0.2+esm4
|
|
| 16.04 LTS xenial |
Fixed in 4.2.1-1ubuntu3.1+esm4
|
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CVSS version:
Base score
8.7 · High
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
Base score
7.5 · High
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
Related Ubuntu Security Notices (USN)
- USN-8952-1
- Tornado vulnerabilities
- 22 October 2026