Amazon Linux 2 (EOS) Security Advisory: ALAS2-2026-3975
Advisory Released Date: 2026-10-12
Advisory Updated Date: 2026-10-12
Severity:
Important
Issue Overview:
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. (CVE-2026-91990)
Affected Packages:
python3-tornado
Note:
This advisory is applicable to Amazon Linux 2 (AL2) Core repository. Visit this FAQ section for the difference between AL2 Core and AL2 Extras advisories.
Issue Correction:
Run yum update python3-tornado or yum update --advisory ALAS2-2026-3975 to update your system.
New Packages:
aarch64:
python3-tornado-5.0.2-4.amzn2.0.11.aarch64
python3-tornado-doc-5.0.2-4.amzn2.0.11.aarch64
python3-tornado-debuginfo-5.0.2-4.amzn2.0.11.aarch64
i686:
python3-tornado-5.0.2-4.amzn2.0.11.i686
python3-tornado-doc-5.0.2-4.amzn2.0.11.i686
python3-tornado-debuginfo-5.0.2-4.amzn2.0.11.i686
src:
python3-tornado-5.0.2-4.amzn2.0.11.src
x86_64:
python3-tornado-5.0.2-4.amzn2.0.11.x86_64
python3-tornado-doc-5.0.2-4.amzn2.0.11.x86_64
python3-tornado-debuginfo-5.0.2-4.amzn2.0.11.x86_64