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Fencer Vulns
high 7.1

CVE-2025-64764 json

Astro is vulnerable to Reflected XSS via the server islands feature

published 2025-11-19 11 mo ago modified 2026-10-18 21 d ago also GHSA-wrwg-2hg8-v723 , EUVD-2025-198184

cvss
7.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits
0
none known, plus a Nuclei check

Summary

Astro is a web framework. Prior to version 5.15.8, a reflected XSS vulnerability is present when the server islands feature is used in the targeted application, regardless of what was intended by the component template(s). This issue has been patched in version 5.15.8.

Patch / fix

  • npm astro 5.15.8
  • astro astro 5.15.8

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
11 mo ago

Exploit prediction

0.53% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • Nuclei template Astro - Reflected XSS via server islands feature nuclei detection template
  • github.com https://github.com/withastro/astro/security/advisories/GHSA-wrwg-2hg8-v723 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N
NVD 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
GitHub 3.1 7.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N

Affected packages

ecosystem package affected fixed in
npm astro
<5.15.8
5.15.8

Affected products

  • withastro astro

Classification

Weakness
  • CWE-80 Improper Neutralization of Script-Related HTML Tags in a Web Page
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Vulns 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.