GHSA-4233-JC72-56C5
Vulnerability from github – Published: 2026-09-30 23:40 – Updated: 2026-09-30 23:40Summary
The @astrojs/netlify adapter generated regular expressions for Netlify Image CDN remote-image allowlists without anchoring them to the beginning of the URL. Netlify evaluates these expressions with RegExp.test(), so an allowed image origin appearing anywhere in a URL, including its path or query string, could satisfy the allowlist.
For example, an application allowing images.example.com could accept a source URL such as:
http://127.0.0.1:6379/?url=https://images.example.com/image.png
The allowlist matched the approved origin in the query string, but Netlify parsed and fetched the URL whose actual host was 127.0.0.1.
Impact
An unauthenticated attacker can bypass the configured image.domains or image.remotePatterns allowlist through the public /.netlify/images endpoint and cause Netlify Image CDN to make requests to attacker-selected URLs. This may allow probing or reaching internal services, depending on Netlify's network-level egress protections.
The Image CDN attempts to transform responses as images, which limits direct response exfiltration. No confidentiality or integrity impact has been demonstrated.
Affected versions
@astrojs/netlify versions from 5.2.0 through 8.2.3.
Patches
Fixed in @astrojs/netlify 8.2.4. Generated remote-image allowlist expressions are now anchored to both the beginning and end of the source URL.
Workarounds
Upgrade to @astrojs/netlify 8.2.4 or later. Before upgrading, disable Netlify Image CDN by setting imageCDN: false in the adapter configuration, or remove remote image allowlist entries.
Credits
Reported by @pacocartones.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 8.2.3"
},
"package": {
"ecosystem": "npm",
"name": "@astrojs/netlify"
},
"ranges": [
{
"events": [
{
"introduced": "5.2.0"
},
{
"fixed": "8.2.4"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-102983"
],
"database_specific": {
"cwe_ids": [
"CWE-625",
"CWE-918"
],
"github_reviewed": true,
"github_reviewed_at": "2026-09-30T23:40:12Z",
"nvd_published_at": "2026-09-30T15:22:22Z",
"severity": "MODERATE"
},
"details": "## Summary\n\nThe `@astrojs/netlify` adapter generated regular expressions for Netlify Image CDN remote-image allowlists without anchoring them to the beginning of the URL. Netlify evaluates these expressions with `RegExp.test()`, so an allowed image origin appearing anywhere in a URL, including its path or query string, could satisfy the allowlist.\n\nFor example, an application allowing `images.example.com` could accept a source URL such as:\n\n```text\nhttp://127.0.0.1:6379/?url=https://images.example.com/image.png\n```\n\nThe allowlist matched the approved origin in the query string, but Netlify parsed and fetched the URL whose actual host was `127.0.0.1`.\n\n## Impact\n\nAn unauthenticated attacker can bypass the configured `image.domains` or `image.remotePatterns` allowlist through the public `/.netlify/images` endpoint and cause Netlify Image CDN to make requests to attacker-selected URLs. This may allow probing or reaching internal services, depending on Netlify\u0027s network-level egress protections.\n\nThe Image CDN attempts to transform responses as images, which limits direct response exfiltration. No confidentiality or integrity impact has been demonstrated.\n\n## Affected versions\n\n`@astrojs/netlify` versions from 5.2.0 through 8.2.3.\n\n## Patches\n\nFixed in `@astrojs/netlify` 8.2.4. Generated remote-image allowlist expressions are now anchored to both the beginning and end of the source URL.\n\n## Workarounds\n\nUpgrade to `@astrojs/netlify` 8.2.4 or later. Before upgrading, disable Netlify Image CDN by setting `imageCDN: false` in the adapter configuration, or remove remote image allowlist entries.\n\n## Credits\n\nReported by @pacocartones.",
"id": "GHSA-4233-jc72-56c5",
"modified": "2026-09-30T23:40:12Z",
"published": "2026-09-30T23:40:12Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/withastro/astro/security/advisories/GHSA-4233-jc72-56c5"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-102983"
},
{
"type": "WEB",
"url": "https://github.com/withastro/astro/pull/17752"
},
{
"type": "WEB",
"url": "https://github.com/withastro/astro/commit/e362d4cf540b27730482455c8fc02efe57d16702"
},
{
"type": "PACKAGE",
"url": "https://github.com/withastro/astro"
},
{
"type": "WEB",
"url": "https://github.com/withastro/astro/releases/tag/@astrojs/netlify@8.2.4"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "Astro: Netlify Image CDN allowlist bypass enables SSRF"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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