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OpenAdvisories
High ALAS2023-2026-3176 1 CVE

Important: python3.13-tornado security update (Amazon Linux 2023)

Published Oct 12, 2026 · Updated Oct 12, 2026

Ecosystem: Amazon Linux

Summary

Package updates are available for Amazon Linux 2023 that fix the following vulnerabilities: CVE-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 memory and causing denial of service.

Fixed packages 4

ReleasePackageFixed in
Amazon Linux · 2023 python3.13-tornado 0:6.4.2-1.amzn2023.0.6
Amazon Linux · 2023 python3.13-tornado-debuginfo 0:6.4.2-1.amzn2023.0.6
Amazon Linux · 2023 python3.13-tornado-debugsource 0:6.4.2-1.amzn2023.0.6
Amazon Linux · 2023 python3.13-tornado-doc 0:6.4.2-1.amzn2023.0.6

Vulnerabilities 1

  • High 7.5
    CVE-2026-91990

    Tornado before 6.5.8 Memory Amplification DoS via multipart

    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, ex…

    tornadoweb tornado python-tornado python-tornado Debian Ubuntu Azure Linux PyPI

References

  • web
    https://alas.aws.amazon.com/cve/html/CVE-2026-91990.html