Astro is a web framework for content-driven websites. From 7.1.0 until 7.3.3, Astro's server-side View Transition CSS generator does not keep string animation properties within their generated declarations. An application that passes attacker-controlled data into properties such as duration, delay, easing, direction, fillMode, or animation names can allow CSS delimiters to terminate the declaration and add attacker-selected rules to the server-rendered page. The generated stylesheet still escapes literal less-than characters, so the injected content cannot terminate the style element or directly inject HTML or JavaScript. The injected CSS can conceal or reposition content, add generated text, and otherwise misrepresent the interface; some applications may also expose data already present in selectable DOM attributes through conditional resource loads. This issue is fixed in 7.3.3.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements Present

User Interaction Passive

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact Low

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
withastro astro affected
Version Status Constraints
>= 7.1.0, < 7.3.3 affected —

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Project Subscriptions

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Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/withastro/astro/commit/0b4dc3a211910b589d3805ab4dfedf11b0e712bb cve-icon cve-icon
https://github.com/withastro/astro/pull/17970 cve-icon cve-icon
https://github.com/withastro/astro/releases/tag/astro@7.3.3 cve-icon cve-icon
https://github.com/withastro/astro/security/advisories/GHSA-mpr7-6m5w-76rw cve-icon cve-icon
History

Wed, 21 Oct 2026 17:45:00 +0000

Type Values Removed Values Added
Description Astro is a web framework for content-driven websites. From 7.1.0 until 7.3.3, Astro's server-side View Transition CSS generator does not keep string animation properties within their generated declarations. An application that passes attacker-controlled data into properties such as duration, delay, easing, direction, fillMode, or animation names can allow CSS delimiters to terminate the declaration and add attacker-selected rules to the server-rendered page. The generated stylesheet still escapes literal less-than characters, so the injected content cannot terminate the style element or directly inject HTML or JavaScript. The injected CSS can conceal or reposition content, add generated text, and otherwise misrepresent the interface; some applications may also expose data already present in selectable DOM attributes through conditional resource loads. This issue is fixed in 7.3.3.
Title Astro: Arbitrary CSS injection in Astro View Transitions
Weaknesses CWE-79
References
Metrics cvssV4_0

{'score': 2.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-21T17:30:03.860Z

Reserved: 2026-10-20T21:53:58.472Z

Link: CVE-2026-114127

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-21T18:17:25.317

Modified: 2026-10-21T18:17:25.317

Link: CVE-2026-114127

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-21T20:30:13Z

Weaknesses