CVE-2026-45028

Astro: Server island encrypted parameters vulnerable to cross-component replay

Published May 13, 2026 CVSS 4.0 · 2.9 Low EPSS < 1% KEV · Not listed
Description
Astro is a web framework. Astro versions prior to 6.1.10 used AES-GCM encryption to protect the confidentiality and integrity of server island props and slots parameters, but did not bind the ciphertext to its intended component or parameter type. An attacker could replay one component's encrypted props (p) value as another component's slots (s) value, or vice versa. Since slots contain raw unescaped HTML while props may contain user-controlled values, this could lead to XSS in applications. This occurs when the application uses server islands, two different server island components share the same key name for a prop and a slot, and an attacker has full control over the value of the overlapping prop (requires a dynamically rendered page). This vulnerability is fixed in 6.1.10.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-xr5h-phrj-8vxv Astro: Server island encrypted parameters vulnerable to cross-component replay
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Astro
Astro astro
Weaknesses CWE-79
CPEs cpe:2.3:a:astro:astro:*:*:*:*:*:node.js:*:*
Vendors & Products Astro
Astro astro
Metrics cvssV3_1

{'score': 6.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'}

Type Values Removed Values Added
First Time appeared Withastro
Withastro astro
Vendors & Products Withastro
Withastro astro
Type Values Removed Values Added
Description Astro is a web framework. Astro versions prior to 6.1.10 used AES-GCM encryption to protect the confidentiality and integrity of server island props and slots parameters, but did not bind the ciphertext to its intended component or parameter type. An attacker could replay one component's encrypted props (p) value as another component's slots (s) value, or vice versa. Since slots contain raw unescaped HTML while props may contain user-controlled values, this could lead to XSS in applications. This occurs when the application uses server islands, two different server island components share the same key name for a prop and a slot, and an attacker has full control over the value of the overlapping prop (requires a dynamically rendered page). This vulnerability is fixed in 6.1.10.
Title Astro: Server island encrypted parameters vulnerable to cross-component replay
Weaknesses CWE-323
References
Metrics cvssV4_0

{'score': 2.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
May 14, 2026, 6:33 PM
Reserved
May 8, 2026, 4:58 PM
Status
Analyzed
Published
May 13, 2026, 4:17 PM
Modified
Oct 26, 2026, 5:10 PM