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.

The remote Debian 12 host has a package installed that is affected by multiple vulnerabilities as referenced in the dla-4711 advisory.

    -------------------------------------------------------------------------     Debian LTS Advisory DLA-4711-1                debian-lts@lists.debian.org     https://www.debian.org/lts/security/                       Daniel Leidert     August 01, 2026                               https://wiki.debian.org/LTS
    -------------------------------------------------------------------------

    Package        : starlette     Version        : 0.26.1-1+deb12u2     CVE ID         : CVE-2026-48817 CVE-2026-54282 CVE-2026-54283     Debian Bug     : 1140631 1140632

    Multiple vulnerabilities were found in starlette, a lightweight ASGI     (Asynchronous Server Gateway Interface) framework/toolkit.

    CVE-2026-48817

       A vulnerability exists where an HTTPEndpoint subclass is registered        through Route() without an explicit methods argument, and the route        does not constrain the method and every method reaches the endpoint.

    CVE-2026-54282

       A vulnerability exists where the HTTP request path is not validated        before being used to reconstruct request.url which can poison        request.url.hostname and request.url.netloc.

    CVE-2026-54283

       The max_fields and max_part_size limits for request.form() are enforced        for multipart/form-data, but silently ignored for application/x-www-        form-urlencoded.

    For Debian 12 bookworm, these problems have been fixed in version     0.26.1-1+deb12u2.

    We recommend that you upgrade your starlette packages.

    For the detailed security status of starlette please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/starlette

    Further information about Debian LTS security advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://wiki.debian.org/LTS     Attachment:
    signature.asc     Description: This is a digitally signed message part

Tenable has extracted the preceding description block directly from the Debian security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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. (CVE-2026-54283)

Note that Nessus relies on the presence of the package as reported by the vendor.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - 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. (CVE-2026-54283)

ID	Name	Product	Family	Type	Severity
331605	Debian dla-4711 : python3-starlette - security update	Nessus	Debian Local Security Checks	Local	medium
322131	Linux Distros Unpatched Vulnerability : CVE-2026-54283	Nessus	Misc.	Local	high
443221	SCA: security update for starlette (GHSA-82w8-qh3p-5jfq)	Tenable Cloud Security	SCA Checks	Local	high
443221	SCA: security update for starlette (GHSA-82w8-qh3p-5jfq)	Tenable Self-Hosted Container Security	SCA Checks	Local	high

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CVE-2026-54283

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