UBUNTU-CVE-2026-33173 (CVE-2026-33173)
Vulnerability from osv_ubuntu – Published: 2026-03-24 00:16 – Updated: 2026-05-20 15:27 – Source website
VLAI
Details
Active Storage allows users to attach cloud and local files in Rails applications. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, 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 direct-upload client can set these flags to skip MIME detection and analysis. This allows an attacker to upload arbitrary content while claiming a safe content_type, bypassing any validations that rely on Active Storage's automatic content type identification. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.
Severity
5.3 (Medium)
N/A (UNKNOWN)
References
{
"affected": [
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "rails",
"binary_version": "2:4.2.6-1ubuntu0.1~esm2"
},
{
"binary_name": "ruby-actionmailer",
"binary_version": "2:4.2.6-1ubuntu0.1~esm2"
},
{
"binary_name": "ruby-actionpack",
"binary_version": "2:4.2.6-1ubuntu0.1~esm2"
},
{
"binary_name": "ruby-actionview",
"binary_version": "2:4.2.6-1ubuntu0.1~esm2"
},
{
"binary_name": "ruby-activejob",
"binary_version": "2:4.2.6-1ubuntu0.1~esm2"
},
{
"binary_name": "ruby-activemodel",
"binary_version": "2:4.2.6-1ubuntu0.1~esm2"
},
{
"binary_name": "ruby-activerecord",
"binary_version": "2:4.2.6-1ubuntu0.1~esm2"
},
{
"binary_name": "ruby-activesupport",
"binary_version": "2:4.2.6-1ubuntu0.1~esm2"
},
{
"binary_name": "ruby-rails",
"binary_version": "2:4.2.6-1ubuntu0.1~esm2"
},
{
"binary_name": "ruby-railties",
"binary_version": "2:4.2.6-1ubuntu0.1~esm2"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:16.04:LTS",
"name": "rails",
"purl": "pkg:deb/ubuntu/rails@2:4.2.6-1ubuntu0.1~esm2?arch=source\u0026distro=esm-apps/xenial"
},
"ranges": [
{
"events": [
{
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}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2:4.1.10-1",
"2:4.2.5-1",
"2:4.2.5.1-1",
"2:4.2.5.2-2",
"2:4.2.6-1",
"2:4.2.6-1ubuntu0.1~esm1",
"2:4.2.6-1ubuntu0.1~esm2"
]
},
{
"ecosystem_specific": {
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{
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},
{
"binary_name": "ruby-actionmailer",
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},
{
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},
{
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},
{
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},
{
"binary_name": "ruby-activemodel",
"binary_version": "2:4.2.10-0ubuntu4+esm2"
},
{
"binary_name": "ruby-activerecord",
"binary_version": "2:4.2.10-0ubuntu4+esm2"
},
{
"binary_name": "ruby-activesupport",
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},
{
"binary_name": "ruby-rails",
"binary_version": "2:4.2.10-0ubuntu4+esm2"
},
{
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"binary_version": "2:4.2.10-0ubuntu4+esm2"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:18.04:LTS",
"name": "rails",
"purl": "pkg:deb/ubuntu/rails@2:4.2.10-0ubuntu4+esm2?arch=source\u0026distro=esm-apps/bionic"
},
"ranges": [
{
"events": [
{
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}
],
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}
],
"versions": [
"2:4.2.9-2",
"2:4.2.9-4",
"2:4.2.10-0ubuntu4",
"2:4.2.10-0ubuntu4+esm1",
"2:4.2.10-0ubuntu4+esm2"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "rails",
"binary_version": "2:5.2.3+dfsg-3ubuntu0.1~esm1"
},
{
"binary_name": "ruby-actioncable",
"binary_version": "2:5.2.3+dfsg-3ubuntu0.1~esm1"
},
{
"binary_name": "ruby-actionmailer",
"binary_version": "2:5.2.3+dfsg-3ubuntu0.1~esm1"
},
{
"binary_name": "ruby-actionpack",
"binary_version": "2:5.2.3+dfsg-3ubuntu0.1~esm1"
},
{
"binary_name": "ruby-actionview",
"binary_version": "2:5.2.3+dfsg-3ubuntu0.1~esm1"
},
{
"binary_name": "ruby-activejob",
"binary_version": "2:5.2.3+dfsg-3ubuntu0.1~esm1"
},
{
"binary_name": "ruby-activemodel",
"binary_version": "2:5.2.3+dfsg-3ubuntu0.1~esm1"
},
{
"binary_name": "ruby-activerecord",
"binary_version": "2:5.2.3+dfsg-3ubuntu0.1~esm1"
},
{
"binary_name": "ruby-activestorage",
"binary_version": "2:5.2.3+dfsg-3ubuntu0.1~esm1"
},
{
"binary_name": "ruby-activesupport",
"binary_version": "2:5.2.3+dfsg-3ubuntu0.1~esm1"
},
{
"binary_name": "ruby-rails",
"binary_version": "2:5.2.3+dfsg-3ubuntu0.1~esm1"
},
{
"binary_name": "ruby-railties",
"binary_version": "2:5.2.3+dfsg-3ubuntu0.1~esm1"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:20.04:LTS",
"name": "rails",
"purl": "pkg:deb/ubuntu/rails@2:5.2.3+dfsg-3ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/focal"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2:5.2.2.1+dfsg-1ubuntu1",
"2:5.2.3+dfsg-3",
"2:5.2.3+dfsg-3ubuntu0.1~esm1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "rails",
"binary_version": "2:6.1.4.1+dfsg-8ubuntu2+esm1"
},
{
"binary_name": "ruby-actioncable",
"binary_version": "2:6.1.4.1+dfsg-8ubuntu2+esm1"
},
{
"binary_name": "ruby-actionmailbox",
"binary_version": "2:6.1.4.1+dfsg-8ubuntu2+esm1"
},
{
"binary_name": "ruby-actionmailer",
"binary_version": "2:6.1.4.1+dfsg-8ubuntu2+esm1"
},
{
"binary_name": "ruby-actionpack",
"binary_version": "2:6.1.4.1+dfsg-8ubuntu2+esm1"
},
{
"binary_name": "ruby-actiontext",
"binary_version": "2:6.1.4.1+dfsg-8ubuntu2+esm1"
},
{
"binary_name": "ruby-actionview",
"binary_version": "2:6.1.4.1+dfsg-8ubuntu2+esm1"
},
{
"binary_name": "ruby-activejob",
"binary_version": "2:6.1.4.1+dfsg-8ubuntu2+esm1"
},
{
"binary_name": "ruby-activemodel",
"binary_version": "2:6.1.4.1+dfsg-8ubuntu2+esm1"
},
{
"binary_name": "ruby-activerecord",
"binary_version": "2:6.1.4.1+dfsg-8ubuntu2+esm1"
},
{
"binary_name": "ruby-activestorage",
"binary_version": "2:6.1.4.1+dfsg-8ubuntu2+esm1"
},
{
"binary_name": "ruby-activesupport",
"binary_version": "2:6.1.4.1+dfsg-8ubuntu2+esm1"
},
{
"binary_name": "ruby-rails",
"binary_version": "2:6.1.4.1+dfsg-8ubuntu2+esm1"
},
{
"binary_name": "ruby-railties",
"binary_version": "2:6.1.4.1+dfsg-8ubuntu2+esm1"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:22.04:LTS",
"name": "rails",
"purl": "pkg:deb/ubuntu/rails@2:6.1.4.1+dfsg-8ubuntu2+esm1?arch=source\u0026distro=esm-apps/jammy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2:6.0.3.7+dfsg-2",
"2:6.1.4.1+dfsg-8ubuntu2",
"2:6.1.4.1+dfsg-8ubuntu2+esm1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "rails",
"binary_version": "2:6.1.7.3+dfsg-3"
},
{
"binary_name": "ruby-actioncable",
"binary_version": "2:6.1.7.3+dfsg-3"
},
{
"binary_name": "ruby-actionmailbox",
"binary_version": "2:6.1.7.3+dfsg-3"
},
{
"binary_name": "ruby-actionmailer",
"binary_version": "2:6.1.7.3+dfsg-3"
},
{
"binary_name": "ruby-actionpack",
"binary_version": "2:6.1.7.3+dfsg-3"
},
{
"binary_name": "ruby-actiontext",
"binary_version": "2:6.1.7.3+dfsg-3"
},
{
"binary_name": "ruby-actionview",
"binary_version": "2:6.1.7.3+dfsg-3"
},
{
"binary_name": "ruby-activejob",
"binary_version": "2:6.1.7.3+dfsg-3"
},
{
"binary_name": "ruby-activemodel",
"binary_version": "2:6.1.7.3+dfsg-3"
},
{
"binary_name": "ruby-activerecord",
"binary_version": "2:6.1.7.3+dfsg-3"
},
{
"binary_name": "ruby-activestorage",
"binary_version": "2:6.1.7.3+dfsg-3"
},
{
"binary_name": "ruby-activesupport",
"binary_version": "2:6.1.7.3+dfsg-3"
},
{
"binary_name": "ruby-rails",
"binary_version": "2:6.1.7.3+dfsg-3"
},
{
"binary_name": "ruby-railties",
"binary_version": "2:6.1.7.3+dfsg-3"
}
]
},
"package": {
"ecosystem": "Ubuntu:24.04:LTS",
"name": "rails",
"purl": "pkg:deb/ubuntu/rails@2:6.1.7.3+dfsg-3?arch=source\u0026distro=noble"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2:6.1.7.3+dfsg-2build1",
"2:6.1.7.3+dfsg-3"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "rails",
"binary_version": "2:7.2.2.1+dfsg-7"
},
{
"binary_name": "ruby-actioncable",
"binary_version": "2:7.2.2.1+dfsg-7"
},
{
"binary_name": "ruby-actionmailbox",
"binary_version": "2:7.2.2.1+dfsg-7"
},
{
"binary_name": "ruby-actionmailer",
"binary_version": "2:7.2.2.1+dfsg-7"
},
{
"binary_name": "ruby-actionpack",
"binary_version": "2:7.2.2.1+dfsg-7"
},
{
"binary_name": "ruby-actiontext",
"binary_version": "2:7.2.2.1+dfsg-7"
},
{
"binary_name": "ruby-actionview",
"binary_version": "2:7.2.2.1+dfsg-7"
},
{
"binary_name": "ruby-activejob",
"binary_version": "2:7.2.2.1+dfsg-7"
},
{
"binary_name": "ruby-activemodel",
"binary_version": "2:7.2.2.1+dfsg-7"
},
{
"binary_name": "ruby-activerecord",
"binary_version": "2:7.2.2.1+dfsg-7"
},
{
"binary_name": "ruby-activestorage",
"binary_version": "2:7.2.2.1+dfsg-7"
},
{
"binary_name": "ruby-activesupport",
"binary_version": "2:7.2.2.1+dfsg-7"
},
{
"binary_name": "ruby-rails",
"binary_version": "2:7.2.2.1+dfsg-7"
},
{
"binary_name": "ruby-railties",
"binary_version": "2:7.2.2.1+dfsg-7"
}
]
},
"package": {
"ecosystem": "Ubuntu:25.10",
"name": "rails",
"purl": "pkg:deb/ubuntu/rails@2:7.2.2.1+dfsg-7?arch=source\u0026distro=questing"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2:6.1.7.3+dfsg-7",
"2:7.2.2.1+dfsg-7"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "rails",
"binary_version": "2:7.2.3+dfsg-2"
},
{
"binary_name": "ruby-actioncable",
"binary_version": "2:7.2.3+dfsg-2"
},
{
"binary_name": "ruby-actionmailbox",
"binary_version": "2:7.2.3+dfsg-2"
},
{
"binary_name": "ruby-actionmailer",
"binary_version": "2:7.2.3+dfsg-2"
},
{
"binary_name": "ruby-actionpack",
"binary_version": "2:7.2.3+dfsg-2"
},
{
"binary_name": "ruby-actiontext",
"binary_version": "2:7.2.3+dfsg-2"
},
{
"binary_name": "ruby-actionview",
"binary_version": "2:7.2.3+dfsg-2"
},
{
"binary_name": "ruby-activejob",
"binary_version": "2:7.2.3+dfsg-2"
},
{
"binary_name": "ruby-activemodel",
"binary_version": "2:7.2.3+dfsg-2"
},
{
"binary_name": "ruby-activerecord",
"binary_version": "2:7.2.3+dfsg-2"
},
{
"binary_name": "ruby-activestorage",
"binary_version": "2:7.2.3+dfsg-2"
},
{
"binary_name": "ruby-activesupport",
"binary_version": "2:7.2.3+dfsg-2"
},
{
"binary_name": "ruby-rails",
"binary_version": "2:7.2.3+dfsg-2"
},
{
"binary_name": "ruby-railties",
"binary_version": "2:7.2.3+dfsg-2"
}
]
},
"package": {
"ecosystem": "Ubuntu:26.04:LTS",
"name": "rails",
"purl": "pkg:deb/ubuntu/rails@2:7.2.3+dfsg-2?arch=source\u0026distro=resolute"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2:7.2.2.1+dfsg-7",
"2:7.2.2.2+dfsg-2",
"2:7.2.3+dfsg-2"
]
}
],
"aliases": [],
"details": "Active Storage allows users to attach cloud and local files in Rails applications. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, `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 direct-upload client can set these flags to skip MIME detection and analysis. This allows an attacker to upload arbitrary content while claiming a safe `content_type`, bypassing any validations that rely on Active Storage\u0027s automatic content type identification. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.",
"id": "UBUNTU-CVE-2026-33173",
"modified": "2026-05-20T15:27:21Z",
"published": "2026-03-24T00:16:00Z",
"references": [
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-33173"
},
{
"type": "REPORT",
"url": "https://www.cve.org/CVERecord?id=CVE-2026-33173"
},
{
"type": "REPORT",
"url": "https://github.com/rails/rails/commit/707c0f1f41f067fdf96d54e99d43b28dfaae7e53"
},
{
"type": "REPORT",
"url": "https://github.com/rails/rails/commit/8fcb934caadc79c8cc4ce53287046d0f67005b3e"
},
{
"type": "REPORT",
"url": "https://github.com/rails/rails/commit/d9502f5214e2198245a4c1defe9cd02a7c8057d0"
},
{
"type": "REPORT",
"url": "https://github.com/rails/rails/releases/tag/v7.2.3.1"
},
{
"type": "REPORT",
"url": "https://github.com/rails/rails/releases/tag/v8.0.4.1"
},
{
"type": "REPORT",
"url": "https://github.com/rails/rails/releases/tag/v8.1.2.1"
},
{
"type": "REPORT",
"url": "https://github.com/rails/rails/security/advisories/GHSA-qcfx-2mfw-w4cg"
}
],
"related": [],
"schema_version": "1.7.0",
"severity": [
{
"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",
"type": "CVSS_V4"
},
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
],
"upstream": [
"CVE-2026-33173"
]
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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