CVE-2026-126081
Action Pack: Possible Strong Parameters bypass in Parameters#each_key
No exploitation reported by the sources we read.
- Published2026-11-10
- WeaknessCWE-915
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
Description
Action Pack is a framework for handling and responding to web requests. Prior to 8.1.4.1 and 8.0.5.2, ActionController::Parameters#each_key delegates to the internal ActiveSupport::HashWithIndifferentAccess that holds the request parameters, so when called with a block it returns that hash instead of the Parameters instance. The hash does not respond to permitted?, so Active Model mass assignment (new, assign_attributes, update) accepts it without raising ActiveModel::ForbiddenAttributesError. An application that passes the return value of each_key to mass assignment could allow a remote, unauthenticated attacker to set attributes that the application does not permit, such as an authorization flag. This is an incomplete fix of CVE-2020-8164, which made each, each_pair and each_value return the Parameters instance but left each_key delegated. An application is affected if it passes the return value of ActionController::Parameters#each_key, called with a block, to mass assignment. Rails itself makes no such call. This issue is fixed in versions 8.1.4.1 and 8.0.5.2.
Timeline
dates in UTC- 2026-11-1021:06CVE publishedCNA
Versions per branch
Products declared by the CNA
As GitHub_M, the CNA that assigned this CVE, declared them in the CVE record; versions as written. NVD lists no product for this CVE yet: this is the only product data so far.
- railsAffected
- = >= 8.1, < 8.1.4.1no fix stated
- = < 8.0.5.2no fix stated
Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-11-10
Neither OSV.dev nor the vendor advisories we read list affected versions for CVE-2026-126081 yet.
Fix
No fix published by the sources we read yet. NVD record
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Metasploit modules
- none listed Metasploit Framework
Sources
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- Published
- 2026-11-10
- Last Modified
- 2026-11-10
- NVD status
- Received
Frequently asked questions
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