CVE-2026-3125Network attack vector

SSRF via backslash path normalization bypass

Published Mar 4, 2026 · Updated Mar 4, 2026

SSRF in OpenNext @opennextjs/cloudflare before 1.17.1 allows remote attackers to fetch and serve arbitrary URLs through a deployed site. The Worker template passes a backslash-containing /cdn-cgi/image/ path through JavaScript URL normalization, turning it into a matching route that fetches an unvalidated destination. Exploitation requires an HTTP client that preserves path backslashes and can expose attacker-controlled content or otherwise inaccessible /cdn-cgi/ assets through the target origin.

CVSS severity7.7
High
EPSS probability0.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in OpenNext @opennextjs/cloudflare before 1.17.1 allows remote attackers to fetch and serve arbitrary URLs through a deployed site. The Worker template passes a backslash-containing /cdn-cgi/image/ path through JavaScript URL normalization, turning it into a matching route that fetches an unvalidated destination. Exploitation requires an HTTP client that preserves path backslashes and can expose attacker-controlled content or otherwise inaccessible /cdn-cgi/ assets through the target origin.

The record

CVE
CVE-2026-3125
Published
Mar 4, 2026
Updated
Mar 4, 2026
Vendor
OpenNext
Product
@opennextjs/cloudflare
Classifications
CWE-918, CWE-706, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 4, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <1.17.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OpenNext · @opennextjs/cloudflareversion=0 <1.17.1

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
7.7Cloudflare, Inc.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 describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
CWE-706Use of Incorrectly-Resolved Name or Reference
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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