# CVE-2026-126361: Astro: XSS via attribute injection in dynamic tag names

Status: published. Published: 2026-11-12. Updated: 2026-11-12.

Astro is a web framework for content-driven websites. Prior to 7.4.5, Astro rendered a string used as a dynamic element name as raw HTML after applying an incomplete character filter. A / in the string could make an HTML parser treat the remainder as attributes, allowing untrusted element-name input to inject event-handler markup. The .astro dynamic-tag renderer, JSX renderer, and MDX renderer were affected, and exploitation required an application to use request-controlled or stored untrusted data as all or part of an element name. This issue is fixed in version 7.4.5.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- withastro / astro: < 7.4.5 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 4.0: 2.3 (low); CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-79, CWE-184

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/withastro/astro/security/advisories/GHSA-mh32-jxcr-mh9f (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/withastro/astro/pull/18520 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/withastro/astro/commit/e023abac912d7cb6af2b9fb5107ef5dabc667096 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/withastro/astro/releases/tag/astro@7.4.5 (CNA: GitHub_M; x_refsource_MISC)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-126361; retrieved 2026-11-12; source updated 2026-11-12

Revision: d46e5ac43f7b5ef4840a981dfe98399d2659857f974ddd211d70c7cbda90000f

Canonical: https://y2.dev/cve/CVE-2026-126361

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