Astro is a web framework for content-driven websites. From 2.9.0 until 7.1.0, Astro's server-side View Transition CSS generator interpolates animation properties into an inline style element without escaping them for CSS and HTML contexts. An attacker-controlled View Transition animation value such as duration can terminate the generated style element and inject arbitrary HTML or JavaScript. The affected code is packages/astro/src/runtime/server/transition.ts; renderTransition passes sheet.toString() into markHTMLString(), while addAnimationProperty serializes duration through toTimeValue() and also handles easing, direction, delay, fillMode, and name. Exploitation requires an on-demand or server-rendered route to pass attacker-controlled data into a View Transition animation definition and can execute arbitrary JavaScript in the affected application's origin, allowing access to sensitive page data and authenticated actions available to the victim. This issue is fixed in version 7.1.0.

The remote Fedora 43 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-3942ab86fd advisory.

    See https://github.com/jupytext/jupytext/blob/main/CHANGELOG.md for changes in versions 1.19.5 and 1.19.6.
    For this update, a patch has been applied that reverses the jupyterlab  jupyter-builder change for     Fedora releases  45, since jupyter-builder is only available in F46 and later.  Many CVEs have been     fixed in this release.


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

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

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

  - Astro is a web framework for content-driven websites. From 2.9.0 until 7.1.0, Astro's server-side View
    Transition CSS generator interpolates animation properties into an inline style element without escaping
    them for CSS and HTML contexts. An attacker-controlled View Transition animation value such as duration
    can terminate the generated style element and inject arbitrary HTML or JavaScript. The affected code is
    packages/astro/src/runtime/server/transition.ts; renderTransition passes sheet.toString() into
    markHTMLString(), while addAnimationProperty serializes duration through toTimeValue() and also handles
    easing, direction, delay, fillMode, and name. Exploitation requires an on-demand or server-rendered route
    to pass attacker-controlled data into a View Transition animation definition and can execute arbitrary
    JavaScript in the affected application's origin, allowing access to sensitive page data and authenticated
    actions available to the victim. This issue is fixed in version 7.1.0. (CVE-2026-73422)

ID	Name	Product	Family	Type	Severity
365513	Fedora 43 : python-jupytext (2026-3942ab86fd)	Nessus	Fedora Local Security Checks	Local	high
445909	SCA: security update for astro (GHSA-4g3v-8h47-v7g6)	Tenable Cloud Security	SCA Checks	Local	medium
445909	SCA: security update for astro (GHSA-4g3v-8h47-v7g6)	Tenable Self-Hosted Container Security	SCA Checks	Local	medium

Detections

Analytics

CVE-2026-73422

medium

Tenable Plugins

high

medium

medium