Quick answers
- Is CVE-2026-126361 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-126361 being exploited in the wild.
- How severe is CVE-2026-126361?
- Informational severity, published 13 November 2026.
- Which products and versions are affected?
- Astro before 7.4.5.
- Is there a fix for CVE-2026-126361?
- Yes: fixed in 7.4.5. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-126361 attacked?
- It is attacked over the network, in a web application.
- Am I affected by CVE-2026-126361?
- Check whether you run Astro at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- Fixed in: 7.4.5
Technical details
The vulnerability exists in Astro's dynamic-tag, JSX, and MDX renderers, which apply incomplete character filtering when rendering string-based element names. A forward slash (/) or equals sign (=) in the element name string can be interpreted as attribute delimiters by the HTML parser, bypassing the filter and allowing injection of event-handler markup. Exploitation requires an application to use request-controlled or stored untrusted data as all or part of a dynamic element name.
Affected products
- Astro Astro before 7.4.5
Timeline
- 2026-11-13: disclosed
- 2026-10-30: patched: Fix merged in commit e023abac912d7cb6af2b9fb5107ef5dabc667096