Astro: Netlify Image CDN allowlist bypass enables SSRF

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

6.3 · 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 · score source

EPSS

• CVE-2026-102983: 0.31% estimated exploitation activity in the next 30 days; percentile 23.98 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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: 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…

Published by the source

30 Sep 2026, 23:40 UTC

Last modified by the source

30 Sep 2026, 23:45 UTC

Source last checked

26 Oct 2026, 13:06 UTC

1. Revision 4 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-4233-jc72-56c5

2. Revision 3 · amended · 24 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-4233-jc72-56c5

4. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-4233-jc72-56c5

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# Patch Next advisory brief: CVE-2026-102983

Advisory: Astro: Netlify Image CDN allowlist bypass enables SSRF
IDs: CVE-2026-102983, GHSA-4233-jc72-56c5
Record: https://patchnext.com/advisories/cve-2026-102983 (revision 4, source checked 26 Oct 2026, 13:06 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @astrojs/netlify 8.2.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @astrojs/netlify: affected >= 5.2.0, <= 8.2.3; fixed in 8.2.4

## Suggested inspection (read-only)
- `npm ls @astrojs/netlify --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on @astrojs/netlify.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-4233-jc72-56c5 (GitHub-reviewed advisory GHSA-4233-jc72-56c5 lists affected ranges: npm @astrojs/netlify >=5.2.0 <=8.2.3)
- Verified: https://osv.dev/vulnerability/GHSA-4233-jc72-56c5 (OSV record GHSA-4233-jc72-56c5 lists affected ranges: npm @astrojs/netlify >=5.2.0 <8.2.4 (fixed))

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