Action Pack: Possible IP spoofing in Action Dispatch RemoteIp

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-126083
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-11-10 21:19:27 UTC
Updated2026-11-10 21:19:27 UTC
DescriptionAction Pack is a framework for handling and responding to web requests. From 8.1 until 8.1.4.1, Since Rails 8.1.0, ActionDispatch::RemoteIp derives request.remote_ip from Rack::Request#forwarded_for, which under Rack 3 reads the RFC 7239 Forwarded header in preference to X-Forwarded-For. When a reverse proxy appends the client address to X-Forwarded-For but passes a client-supplied Forwarded header through unchanged, request.remote_ip returns an address chosen by the client, and the IP spoofing check does not raise, because it compares only Client-Ip with the forwarded addresses. An unauthenticated attacker could therefore spoof request.remote_ip, possibly bypassing IP-based access controls and rate limits keyed on the client address (including the default by: of rate_limit), and falsifying the client address in logs. An application is affected if it meets all of these requirements: Runs Rails 8.1.0 through 8.1.4 with Rack 3. Under Rack 2.2, forwarded_for reads only X-Forwarded-For. Is served behind a proxy that does not remove or overwrite a client-supplied Forwarded header. Relies on request.remote_ip for access control, rate limiting, or auditing. The fix detects a spoofed Forwarded header only when the proxy also sets X-Forwarded-For. An application whose proxy passes a client-supplied Forwarded header through and sets no X-Forwarded-For remains exposed after upgrading, and should configure the proxy to remove or overwrite Forwarded, or apply the workaround below. This issue is fixed in version 8.1.4.1.

Risk And Classification

Primary CVSS: v3.0 7.4 HIGH from [email protected]

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Problem Types: CWE-348 | CWE-348 CWE-348: Use of Less Trusted Source

VersionSourceTypeScoreSeverityVector
3.0[email protected]Secondary7.4HIGHCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
3.0CNADECLARED7.4HIGHCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS v3.0 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Rails Rails affected >= 8.1, < 8.1.4.1 Not specified

References

ReferenceSourceLinkTags
github.com/rails/rails/security/advisories/GHSA-2gff-2mmg-m73p [email protected] github.com
github.com/rails/rails/releases/tag/v8.1.4.1 [email protected] github.com
github.com/rails/rails/commit/2a01a5ac521184419d9a92fa2c25e102e68cd227 [email protected] github.com
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