CVE-2025-6087 — @opennextjs/cloudflare
Fix: opennextjs/opennextjs-cloudflare#1147CVE-2025-6087 is a Server-Side Request Forgery (SSRF) vulnerability in @opennextjs/cloudflare. A fix is available for @opennextjs/cloudflare — see the affected versions and patch details below.
SSRF vulnerability in opennextjs-cloudflare via /_next/image endpoint
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-6087.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
@opennextjs/cloudflarenpmDescription
A Server-Side Request Forgery (SSRF) vulnerability was identified in the @opennextjs/cloudflare package, resulting from a path normalization bypass in the /cdn-cgi/image/ handler.
The @opennextjs/cloudflare worker template includes a /cdn-cgi/image/ handler intended for development use only. In production, Cloudflare's edge intercepts /cdn-cgi/image/ requests before they reach the Worker. However, by substituting a backslash for a forward slash (/cdn-cgi\image/ instead of /cdn-cgi/image/), an attacker can bypass edge interception and have the request reach the Worker directly. The JavaScript URL class then normalizes the backslash to a forward slash, causing the request to match the handler and trigger an unvalidated fetch of arbitrary remote URLs.
For example: https://victim-site.com/cdn-cgi\image/aaaa/https://attacker.com
In this example, attacker-controlled content from attacker.com is served through the victim site's domain (victim-site.com), violating the same-origin policy and potentially misleading users or other services.
Note: This bypass only works via HTTP clients that preserve backslashes in paths (e.g., curl --path-as-is). Browsers normalize backslashes to forward slashes before sending requests.
Additionally, Cloudflare Workers with Assets and Cloudflare Pages suffer from a similar vulnerability. Assets stored under /cdn-cgi/ paths are not publicly accessible under normal conditions. However, using the same backslash bypass (/cdn-cgi... instead of /cdn-cgi/...), these assets become publicly accessible. This could be used to retrieve private data. For example, Open Next projects store incremental cache data under /cdn-cgi/_next_cache, which could be exposed via this bypass.
Impact
- SSRF via path normalization bypass of Cloudflare edge interception
- Arbitrary remote content loading under the victim site's domain
- Same-origin policy bypass
- Potential for infrastructure abuse (scanning from Cloudflare IP space, worker resource exhaustion)
- Exposure of private assets stored under /cdn-cgi/ paths. For example, Open Next projects store incremental cache data under /cdn-cgi/_next_cache, which could be exposed via this bypass.
Credits
Disclosed responsibly by security researcher @Ezzer17.
Mitigations
The following mitigations have been put in place:
Server-side updates to Cloudflare's Workers platform to block backslash path normalization bypasses for /cdn-cgi requests. The update automatically mitigates the issue for all existing and any future sites deployed to Cloudflare Workers.
In addition to the platform level fix, Root cause fix has been implemented to the Cloudflare adapter for Open Next. The patched version of the adapter is found at @opennextjs/[email protected] (https://www.npmjs.com/package/@opennextjs/cloudflare)
Dependency update to the Next.js template used with create-cloudflare (c3) to use the fixed version of the Cloudflare adapter for Open Next. Despite the automatic mitigation deployed on Cloudflare's platform, we encourage affected users to upgrade to the patched version of @opennextjs/cloudflare.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @opennextjs/cloudflare | all versions | 1.17.1npm install @opennextjs/cloudflare@1.17.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @opennextjs/cloudflare, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @opennextjs/cloudflare to 1.17.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-6087 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-6087 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-6087. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-6087 in your dependencies?
O3 Security finds CVE-2025-6087 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.