CVE-2026-33173: Activestorage Rails Active Storage Has Possible Vulnerability
MODERATECVE-2026-33173 is a MODERATE rails active storage has possible vulnerability (CWE-925: Improper Verification of Intent by Broadcast Receiver) affecting Activestorage libraries in the RubyGems ecosystem. The issue involves rails active storage has possible content type bypass via metadata in direct uploads. Remediation is available by upgrading affected packages to version 8.1.2.1, 8.0.4.1, 7.2.3.1.
CVE-2026-33173 at a Glance
How to Fix CVE-2026-33173
To remediate this vulnerability, upgrade all affected Activestorage dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Upgrade activestorage to 8.1.2.1Upgrade activestorage to 8.0.4.1Upgrade activestorage to 7.2.3.1Run the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for activestorageHow to Check if You Are Affected
To determine whether your application is affected by CVE-2026-33173, inspect your project dependencies for Activestorage:
inspect dependencies for activestorageAnalyze the terminal output to locate any version of Activestorage in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 8.1.2.1), your application is affected.
Note: Verify declared build manifests and deployed runtime container environments.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-925: Improper Verification of Intent by Broadcast Receiver, where the android application uses a broadcast receiver that receives an intent but does not properly verify that the intent came from an authorized source. In Activestorage, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2026-33173 Affected Activestorage Versions
3 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
activestorage
|
RubyGems |
≥ 8.1.0.beta1
< 8.1.2.1
|
8.1.2.1
|
|
activestorage
|
RubyGems |
≥ 8.0.0.beta1
< 8.0.4.1
|
8.0.4.1
|
|
activestorage
|
RubyGems |
< 7.2.3.1
|
7.2.3.1
|
References
Frequently Asked Questions
What is CVE-2026-33173?
Which Activestorage versions are affected?
What version fixes CVE-2026-33173?
Is activestorage affected?
What CWE is associated with CVE-2026-33173?
How can I check RubyGems dependencies for CVE-2026-33173?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-qcfx-2mfw-w4cg",
"modified" : "2026-05-13T16:15:54Z",
"published" : "2026-03-23T20:54:16Z",
"aliases" : [ "CVE-2026-33173" ],
"summary" : "Rails Active Storage has possible content type bypass via metadata in direct uploads",
"details" : "### Impact\nActive Storage's `DirectUploadsController` accepts arbitrary metadata from the client and persists it on the blob. Because internal flags like `identified` and `analyzed` are stored in the same metadata hash, a malicious direct-upload client could set these flags.\n\n### Releases\nThe fixed releases are available at the normal locations.\n\n### Credit\nThis was responsible reported by Hackerone researcher [pwnie](https://hackerone.com/pwnie)",
"severity" : [ {
"type" : "CVSS_V4",
"score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "RubyGems",
"name" : "activestorage"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "8.1.0.beta1"
}, {
"fixed" : "8.1.2.1"
} ]
} ]
}, {
"package" : {
"ecosystem" : "RubyGems",
"name" : "activestorage"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "8.0.0.beta1"
}, {
"fixed" : "8.0.4.1"
} ]
} ]
}, {
"package" : {
"ecosystem" : "RubyGems",
"name" : "activestorage"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "7.2.3.1"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/rails/rails/security/advisories/GHSA-qcfx-2mfw-w4cg"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-33173"
}, {
"type" : "WEB",
"url" : "https://github.com/rails/rails/commit/707c0f1f41f067fdf96d54e99d43b28dfaae7e53"
}, {
"type" : "WEB",
"url" : "https://github.com/rails/rails/commit/8fcb934caadc79c8cc4ce53287046d0f67005b3e"
}, {
"type" : "WEB",
"url" : "https://github.com/rails/rails/commit/d9502f5214e2198245a4c1defe9cd02a7c8057d0"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/rails/rails"
}, {
"type" : "WEB",
"url" : "https://github.com/rails/rails/releases/tag/v7.2.3.1"
}, {
"type" : "WEB",
"url" : "https://github.com/rails/rails/releases/tag/v8.0.4.1"
}, {
"type" : "WEB",
"url" : "https://github.com/rails/rails/releases/tag/v8.1.2.1"
}, {
"type" : "WEB",
"url" : "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/activestorage/CVE-2026-33173.yml"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-925" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2026-03-23T20:54:16Z",
"nvd_published_at" : "2026-03-24T00:16:28Z"
}
}