CVE-2026-54298 json
Astro: XSS via Unescaped Attribute Names in Spread Props
published 4mo ago modified 17d ago also EUVD-2026-38336 , GHSA-jrpj-wcv7-9fh9
- cvss
- 4.2
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 13%
- public exploits
- 0
- none known
Summary
Astro is a web framework. Prior to 6.4.6, the spreadAttributes function in Astro's server-side rendering pipeline iterates over object keys and passes them directly to addAttribute, which interpolates the key into the HTML output without escaping. When a developer uses the spread syntax {...props} on an HTML element and the object keys come from an untrusted source (API, CMS, URL parameters), an attacker can inject arbitrary HTML attributes including event handlers like onmousemove, onclick, or break out of the attribute context entirely to inject new elements. This vulnerability is fixed in 6.4.6.
Patch / fix
- npm astro 6.4.6
- astro astro 6.4.6
Is CVE-2026-54298 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerCISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- partial
- Assessed
- 4mo ago
Exploit prediction
0.23% chance of exploitation in the next 30 days, higher than 13% of all scored CVEs (FIRST EPSS, 2026-11-11).
Exploits and checks
- github.com https://github.com/withastro/astro/security/advisories/GHSA-jrpj-wcv7-9fh9 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 4.2 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N |
| GitHub | 3.1 | 4.2 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N |
| NVD | 3.1 | 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | astro | <6.4.6 |
6.4.6 |
Affected products
- withastro astro
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
References
-
github.com
/withastro/astro/security/advisories/GHSA-jrpj-wcv7-9fh9
exploit, web, vendor-advisory, advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-54298
advisory
-
github.com
/withastro/astro
package
Sources
- CVE List CVE-2026-54298
- GitHub Advisory GHSA-jrpj-wcv7-9fh9
- NVD CVE-2026-54298
- Maintainer advisory GHSA-jrpj-wcv7-9fh9
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
The maintainers of withastro/astro published their own advisory on GitHub. Reviewed sources take precedence over it.