CVE-2026-102983: Astro: Netlify Image CDN allowlist bypass enables SSRF
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:
text 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.
Other sources
Astro is a web framework for content-driven websites. From 5.2.0 until 8.2.4, the @astrojs/netlify adapter generates regular expressions for Netlify Image CDN remote-image allowlists without anchoring them to the beginning of the URL. Because Netlify evaluates these expressions with RegExp.test(), an allowed origin appearing only in a source URL's path or query can satisfy image.domains or image.remotePatterns while the URL's actual host remains attacker-controlled. An unauthenticated request to the public /.netlify/images endpoint can therefore cause the Image CDN to request attacker-selected URLs and may probe or reach internal services. Netlify egress protections may constrain reachable targets, and image transformation limits direct response exfiltration; no confidentiality or integrity impact has been demonstrated. This issue is fixed in version 8.2.4.
— MITRE
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
npm/@astrojs/netlifyto a version that resolves this vulnerability.Fixed in 8.2.4 - Upgrade
Upgrade
@astrojs/netlifyto a version that resolves this vulnerability.Fixed in 8.2.4 - Configuration
Disable Netlify Image CDN by setting imageCDN: false in the adapter configuration before upgrading.
Netlify Image CDN imageCDN = false - Configuration
Remove remote image allowlist entries before upgrading.
Netlify Image CDN remote image allowlist entries = removed
Event History
Frequently Asked Questions
Which deployments are exposed?
Deployments using the @astrojs/netlify adapter from version 5.2.0 through 8.2.3 are affected when Netlify Image CDN remote-image allowlists are configured through image.domains or image.remotePatterns. The vulnerable request path is the public /.netlify/images endpoint.
What does an attacker need to exploit this issue?
An attacker only needs to send an unauthenticated request to the public image endpoint. They can craft a source URL whose path or query contains an allowed origin while its actual host is attacker-controlled.
Does the configured allowlist prevent exploitation?
No. The flaw allows an approved origin to appear anywhere in the URL path or query, causing the generated regular expression to match even when the URL host is not allowlisted.
What limits the impact?
Netlify egress protections may limit which internal or external targets can be reached. Image transformation limits direct response exfiltration, and no confidentiality or integrity impact has been demonstrated.
What is the remediation?
Upgrade @astrojs/netlify to version 8.2.4, which fixes the allowlist matching issue.