Starlette is a lightweight ASGI framework/toolkit. Prior to version 1.0.1, the HTTP `Host` request header was not validated before being used to reconstruct `request.url`. Because the routing algorithm relies on the raw HTTP path while `request.url` is rebuilt from the `Host` header, a malformed header could make `request.url.path` differ from the path that was actually requested. Middleware and endpoints that apply security restrictions based on `request.url` (rather than the raw `scope` path) could therefore be bypassed. Users should upgrade to a version greater than or equal to version 1.0.1, which validates the `Host` header against the grammar of RFC 9112 §3.2 / RFC 3986 §3.2.2 when constructing `request.url` and falls back to `scope["server"]` for malformed values.

The remote Fedora 43 host has a package installed that is affected by a vulnerability as referenced in the FEDORA-2026-e0f378428e advisory.

    Backport fix for CVE-2026-48710

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

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

The remote Fedora 44 host has a package installed that is affected by a vulnerability as referenced in the FEDORA-2026-3bce8d3f11 advisory.

    Backport fix for CVE-2026-48710

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

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

The remote Debian 12 / 13 host has a package installed that is affected by multiple vulnerabilities as referenced in the dsa-6302 advisory.

    - -------------------------------------------------------------------------     Debian Security Advisory DSA-6302-1                   security@debian.org     https://www.debian.org/security/                       Moritz Muehlenhoff     May 27, 2026                          https://www.debian.org/security/faq
    - -------------------------------------------------------------------------

    Package        : starlette     CVE ID         : CVE-2026-48710

    It was discovered that missing validation of Host: headers in the     Starlette ASGI framework could result in a bypass of security checks.

    For the oldstable distribution (bookworm), this problem has been fixed     in version 0.26.1-1+deb12u1. This update also resolves three additional     security issues (CVE-2023-29159, CVE-2024-47874 and CVE-2025-54121).

    For the stable distribution (trixie), this problem has been fixed in     version 0.46.1-3+deb13u2.

    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 Security Advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://www.debian.org/security/

    Mailing list: debian-security-announce@lists.debian.org

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. Prior to version 1.0.1, the HTTP `Host` request header     was not validated before being used to reconstruct `request.url`. Because the routing algorithm relies on     the raw HTTP path while `request.url` is rebuilt from the `Host` header, a malformed header could make     `request.url.path` differ from the path that was actually requested. Middleware and endpoints that apply     security restrictions based on `request.url` (rather than the raw `scope` path) could therefore be     bypassed. Users should upgrade to a version greater than or equal to version 1.0.1, which validates the     `Host` header against the grammar of RFC 9112 3.2 / RFC 3986 3.2.2 when constructing `request.url` and     falls back to `scope[server]` for malformed values. (CVE-2026-48710)

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

ID	Name	Product	Family	Severity
318780	Fedora 43 : python-starlette (2026-e0f378428e)	Nessus	Fedora Local Security Checks	medium
318768	Fedora 44 : python-starlette (2026-3bce8d3f11)	Nessus	Fedora Local Security Checks	medium
317342	Debian dsa-6302 : python3-starlette - security update	Nessus	Debian Local Security Checks	high
316593	Linux Distros Unpatched Vulnerability : CVE-2026-48710	Nessus	Misc.	medium

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CVE-2026-48710

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