GHSA-4233-jc72-56c5

Suggest an improvement
Source
https://github.com/advisories/GHSA-4233-jc72-56c5
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-4233-jc72-56c5/GHSA-4233-jc72-56c5.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-4233-jc72-56c5
Aliases
Published
2026-09-30T23:40:12Z
Modified
2026-09-30T23:45:04Z
Severity
  • 6.3 (Medium) CVSS_V4 - 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 CVSS Calculator
Summary
Astro: Netlify Image CDN allowlist bypass enables SSRF
Details

Summary

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.

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"
}
References

Affected packages

npm / @astrojs/netlify

Package

Name
@astrojs/netlify
View open source insights on deps.dev
Purl
pkg:npm/%40astrojs/netlify

Affected ranges

Type
SEMVER
Events
Introduced
5.2.0
Fixed
8.2.4

Database specific

last_known_affected_version_range 
"<= 8.2.3"
source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-4233-jc72-56c5/GHSA-4233-jc72-56c5.json"