p PatchFirst

CVE-2026-54283

CVE-2026-54283 · Starlette: request.form() limits silently ignored for application/x-www-form-urlencoded enable DoS

This page contains facts from public vulnerability sources. Check the original advisory before updating.

Starlette is a lightweight ASGI framework/toolkit. From 0.4.1 until 1.3.1, request.form() accepts max_fields and max_part_size to bound resource consumption while parsing form data. These limits are enforced for multipart/form-data, but silently ignored for application/x-www-form-urlencoded. An unauthenticated attacker can therefore send a urlencoded body with an arbitrarily large number of fields or an arbitrarily large field, even when the application configured limits it believed would apply. This vulnerability is fixed in 1.3.1.

CVSS 7.5 · High · EPSS 0.5% · Fix available

Published
Updated

Stack: system · python

Affected products and versions

  • starlette

    Versions
    • >= 0.4.1, < 1.3.1: Affected

    No fix published

  • starlette Debian:12

    Versions
    • 0.26.1-1
    • 0.26.1-1+deb12u1
    Affected ranges
    • ECOSYSTEM: < 0.26.1-1+deb12u2

    Update to 0.26.1-1+deb12u2

  • starlette Debian:13

    Versions
    • 0.46.1-3
    • 0.46.1-3+deb13u1
    • 0.46.1-3+deb13u2
    Affected ranges
    • ECOSYSTEM: < 0.46.1-3+deb13u3

    Update to 0.46.1-3+deb13u3

  • starlette Debian:14

    Versions
    • 0.46.1-3
    • 0.50.0-1
    • 1.0.0-1
    • 1.1.0-1
    Affected ranges
    • ECOSYSTEM: < 1.3.1-1

    Update to 1.3.1-1

  • starlette PyPI

    Versions
    • 0.10.0
    • 0.10.1
    • 0.10.2
    • 0.10.3
    • 0.10.4
    • 0.10.5
    • 0.10.6
    • 0.10.7
    • 0.11.0
    • 0.11.1
    • 0.11.2
    • 0.11.3
    • 0.11.4
    • 0.12.0
    • 0.12.0b1
    • 0.12.0b2
    • 0.12.0b3
    • 0.12.1
    • 0.12.10
    • 0.12.11
    • 0.12.12
    • 0.12.13
    • 0.12.2
    • 0.12.3
    • 0.12.4
    • 0.12.5
    • 0.12.6
    • 0.12.7
    • 0.12.8
    • 0.12.9
    • 0.13.0
    • 0.13.1
    • 0.13.2
    • 0.13.3
    • 0.13.4
    • 0.13.5
    • 0.13.6
    • 0.13.7
    • 0.13.8
    • 0.14.0
    • 0.14.1
    • 0.14.2
    • 0.15.0
    • 0.16.0
    • 0.17.0
    • 0.17.1
    • 0.18.0
    • 0.19.0
    • 0.19.1
    • 0.20.0
    • 0.20.1
    • 0.20.2
    • 0.20.3
    • 0.20.4
    • 0.21.0
    • 0.22.0
    • 0.23.0
    • 0.23.1
    • 0.24.0
    • 0.25.0
    • 0.26.0
    • 0.26.0.post1
    • 0.26.1
    • 0.27.0
    • 0.28.0
    • 0.29.0
    • 0.30.0
    • 0.31.0
    • 0.31.1
    • 0.32.0
    • 0.32.0.post1
    • 0.33.0
    • 0.34.0
    • 0.35.0
    • 0.35.1
    • 0.36.0
    • 0.36.1
    • 0.36.2
    • 0.36.3
    • 0.37.0
    • 0.37.1
    • 0.37.2
    • 0.38.0
    • 0.38.1
    • 0.38.2
    • 0.38.3
    • 0.38.4
    • 0.38.5
    • 0.38.6
    • 0.39.0
    • 0.39.1
    • 0.39.2
    • 0.4.1
    • 0.4.2
    • 0.40.0
    • 0.41.0
    • 0.41.1
    • 0.41.2
    • 0.41.3
    • 0.42.0
    • 0.43.0
    • 0.44.0
    • 0.45.0
    • 0.45.1
    • 0.45.2
    • 0.45.3
    • 0.46.0
    • 0.46.1
    • 0.46.2
    • 0.47.0
    • 0.47.1
    • 0.47.2
    • 0.47.3
    • 0.48.0
    • 0.49.0
    • 0.49.1
    • 0.49.2
    • 0.49.3
    • 0.5.0
    • 0.5.1
    • 0.5.2
    • 0.5.3
    • 0.5.4
    • 0.5.5
    • 0.50.0
    • 0.51.0
    • 0.52.0
    • 0.52.1
    • 0.6.0
    • 0.6.1
    • 0.6.2
    • 0.6.3
    • 0.7.0
    • 0.7.1
    • 0.7.2
    • 0.7.3
    • 0.7.4
    • 0.8.0
    • 0.8.1
    • 0.8.2
    • 0.8.3
    • 0.8.4
    • 0.8.5
    • 0.8.6
    • 0.8.7
    • 0.8.8
    • 0.9.0
    • 0.9.1
    • 0.9.10
    • 0.9.11
    • 0.9.2
    • 0.9.3
    • 0.9.4
    • 0.9.5
    • 0.9.6
    • 0.9.7
    • 0.9.8
    • 0.9.9
    • 1.0.0
    • 1.0.0rc1
    • 1.0.1
    • 1.1.0
    • 1.2.0
    • 1.2.1
    • 1.3.0
    Affected ranges
    • ECOSYSTEM: ≥ 0.4.1, < 1.3.1

    Update to 1.3.1

  • starlette Ubuntu:22.04:LTS

    Versions
    • 0.14.1-1
    • 0.16.0-1
    • 0.18.0-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • starlette Ubuntu:24.04:LTS

    Versions
    • 0.30.0-1
    • 0.31.1-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • starlette Ubuntu:25.10

    Versions
    • 0.46.1-2
    • 0.46.1-3
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • starlette Ubuntu:26.10

    Versions
    • 0.50.0-1
    • 1.1.0-1
    • 1.3.1-1
    • 1.7.0-2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • starlette Ubuntu:26.04:LTS

    Versions
    • 0.46.1-3
    • 0.50.0-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

Check your server →