CVE-2026-91990

EUVD-2026-78661
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
VulnCheckCNA
7.5 HIGH
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Base Score
CVSS 3.x
EPSS Score
Percentile: 36.67%
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources (CNA/ADP records, vendor advisories, Enginsight analysis).
VendorProductVersionSource
tornadowebtornado
𝑥
< 6.5.8
CNA
Debian logo
Debian Releases
Debian Product
Codename
python-tornado
bookworm
vulnerable
bookworm (security)
vulnerable
forky
vulnerable
sid
vulnerable
trixie
no-dsa
trixie (security)
vulnerable
Ubuntu logo
Ubuntu Releases
Ubuntu Product
Codename
python-tornado
bionic
Fixed in 4.5.3-1ubuntu0.2+esm4
released
focal
Fixed in 6.0.3+really5.1.1-3ubuntu0.1~esm6
released
jammy
Fixed in 6.1.0-3ubuntu0.1~esm6
released
noble
Fixed in 6.4.0-1ubuntu0.6
released
resolute
Fixed in 6.5.4-0.1ubuntu0.2
released
stonking
Fixed in 6.5.5-5ubuntu1
released
xenial
Fixed in 4.2.1-1ubuntu3.1+esm4
released
openSUSE logo
openSUSE / SLES Releases
openSUSE Product
Release
python3-tornado
suse enterprise sap 15 SP4
4.5.3-150000.3.31.1
fixed
suse enterprise sap 15 SP5
4.5.3-150000.3.31.1
fixed
suse enterprise sap 15 SP6
4.5.3-150000.3.31.1
fixed
suse enterprise server 15 SP4
4.5.3-150000.3.31.1
fixed
suse enterprise server 15 SP5
4.5.3-150000.3.31.1
fixed
suse enterprise server 15 SP6
4.5.3-150000.3.31.1
fixed
python311-tornado6
suse enterprise desktop 15 SP7
6.3.2-150400.9.27.1
fixed
suse enterprise sap 15 SP4
6.3.2-150400.9.27.1
fixed
suse enterprise sap 15 SP5
6.3.2-150400.9.27.1
fixed
suse enterprise sap 15 SP6
6.3.2-150400.9.27.1
fixed
suse enterprise sap 15 SP7
6.3.2-150400.9.27.1
fixed
suse enterprise server 15 SP4
6.3.2-150400.9.27.1
fixed
suse enterprise server 15 SP5
6.3.2-150400.9.27.1
fixed
suse enterprise server 15 SP6
6.3.2-150400.9.27.1
fixed
suse enterprise server 15 SP7
6.3.2-150400.9.27.1
fixed
Red Hat logo
Red Hat Enterprise Linux Releases
Red Hat Product
Release
python3-tornado
RHEL 9
0:6.5.8-0.el9_8.1
fixed
Amazon Linux logo
Amazon Linux Releases
Amazon Package
Release
python-tornado
Amazon Linux 2
0:4.2.1-3.amzn2.0.8
fixed
python-tornado-debuginfo
Amazon Linux 2
0:4.2.1-3.amzn2.0.8
fixed
python-tornado-debugsource
Amazon Linux 2023
0:6.1.0-2.amzn2023.0.11
fixed
python-tornado-doc
Amazon Linux 2
0:4.2.1-3.amzn2.0.8
fixed
Amazon Linux 2023
0:6.1.0-2.amzn2023.0.11
fixed
python3-tornado
Amazon Linux 2
0:5.0.2-4.amzn2.0.11
fixed
Amazon Linux 2023
0:6.1.0-2.amzn2023.0.11
fixed
python3-tornado-debuginfo
Amazon Linux 2
0:5.0.2-4.amzn2.0.11
fixed
Amazon Linux 2023
0:6.1.0-2.amzn2023.0.11
fixed
python3-tornado-doc
Amazon Linux 2
0:5.0.2-4.amzn2.0.11
fixed
python3.13-tornado
Amazon Linux 2023
0:6.4.2-1.amzn2023.0.6
fixed
python3.13-tornado-debuginfo
Amazon Linux 2023
0:6.4.2-1.amzn2023.0.6
fixed
python3.13-tornado-debugsource
Amazon Linux 2023
0:6.4.2-1.amzn2023.0.6
fixed
python3.13-tornado-doc
Amazon Linux 2023
0:6.4.2-1.amzn2023.0.6
fixed
Common Weakness Enumeration
References
https://github.com/tornadoweb/tornado/security/advisories/GHSA-8423-8fgw-73vq
https://www.vulncheck.com/advisories/tornado-before-6.5.8-memory-amplification-dos-via-multipart
https://github.com/tornadoweb/tornado/security/advisories/GHSA-8423-8fgw-73vq