CVE-2026-33173
Rails Active Storage has possible content type bypass via metadata in direct uploads
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Passive
What an attacker can affect
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Rails Active Storage has possible content type bypass via metadata in direct uploads
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.
- Record
CVE-2026-33173- CVSS 4.0
- 5.3 Medium
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 - Weakness
- CWE-925
- Updated
- 2026-11-02
EUVDEUVD-2026-14626
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.
- Record
EUVD-2026-14626- CVSS 4.0
- 5.3 Medium
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 - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-qcfx-2mfw-w4cg
Rails Active Storage has possible content type bypass via metadata in direct uploads
Impact
Active 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.
Releases
The fixed releases are available at the normal locations.
Credit
This was responsible reported by Hackerone researcher pwnie
- Record
GHSA-qcfx-2mfw-w4cg- CVSS 4.0
- 5.3 Medium
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 - Weakness
- CWE-925
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-33173- CVSS 4.0
- 5.3 Medium
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - Weakness
- CWE-925
- Updated
- 2026-11-02
OSV
Rails Active Storage has possible content type bypass via metadata in direct uploads
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.
- Record
CVE-2026-33173- CVSS 4.0
- 5.3 Medium
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 - Weakness
- CWE-925
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-33173
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.
- Record
DEBIAN-CVE-2026-33173- CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - Updated
- 2026-11-02
OSVGHSA-qcfx-2mfw-w4cg
Rails Active Storage has possible content type bypass via metadata in direct uploads
Impact
Active 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.
Releases
The fixed releases are available at the normal locations.
Credit
This was responsible reported by Hackerone researcher pwnie
- Record
GHSA-qcfx-2mfw-w4cg- CVSS 4.0
- 5.3 Medium
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 - Weakness
- CWE-925
- Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-33173
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.
- Record
UBUNTU-CVE-2026-33173- CVSS 4.0
- 5.3 Medium
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 - CVSS 3.1
- 5.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
activestorageRubyGems |
8.1.0.beta1 up to 8.1.2.1 | 8.1.2.1 |
activestorageRubyGems |
8.0.0.beta1 up to 8.0.4.1 | 8.0.4.1 |
activestorageRubyGems |
before 7.2.3.1 | 7.2.3.1 |
railsDebian:12 |
before 2:6.1.7.10+dfsg-1~deb12u3, plus listed versions 2:6.1.7.10+dfsg-1~deb12u12:6.1.7.10+dfsg-1~deb12u22:6.1.7.3+dfsg-12:6.1.7.3+dfsg-102:6.1.7.3+dfsg-11 Show 12 moreShow less2:6.1.7.3+dfsg-122:6.1.7.3+dfsg-132:6.1.7.3+dfsg-22:6.1.7.3+dfsg-2~deb12u12:6.1.7.3+dfsg-32:6.1.7.3+dfsg-42:6.1.7.3+dfsg-52:6.1.7.3+dfsg-62:6.1.7.3+dfsg-72:6.1.7.3+dfsg-7~exp12:6.1.7.3+dfsg-82:6.1.7.3+dfsg-9 |
2:6.1.7.10+dfsg-1~deb12u3 |
railsDebian:13 |
before 2:7.2.2.2+dfsg-2~deb13u2, plus listed versions 2:7.2.2.1+dfsg-72:7.2.2.2+dfsg-12:7.2.2.2+dfsg-2~deb13u1 |
2:7.2.2.2+dfsg-2~deb13u2 |
railsDebian:14 |
before 2:7.2.3.1+dfsg-1, plus listed versions 2:7.2.2.1+dfsg-72:7.2.2.2+dfsg-12:7.2.2.2+dfsg-22:7.2.2.2+dfsg-2~deb13u12:7.2.2.2+dfsg-2~deb13u22:7.2.3+dfsg-12:7.2.3+dfsg-22:7.2.3+dfsg-3 |
2:7.2.3.1+dfsg-1 |
activestorageRubyGems |
8.1.0.beta1 up to 8.1.2.1, plus listed versions 8.1.08.1.0.rc18.1.18.1.2 |
8.1.2.1 |
activestorageRubyGems |
8.0.0.beta1 up to 8.0.4.1, plus listed versions 8.0.08.0.0.18.0.0.rc18.0.0.rc28.0.1 Show 4 moreShow less8.0.28.0.2.18.0.38.0.4 |
8.0.4.1 |
activestorageRubyGems |
before 7.2.3.1, plus listed versions 0.15.2.05.2.0.beta15.2.0.beta25.2.0.rc1 Show 45 moreShow less5.2.0.rc25.2.15.2.1.15.2.1.rc15.2.25.2.2.15.2.2.rc15.2.35.2.3.rc15.2.45.2.4.15.2.4.25.2.4.35.2.4.45.2.4.55.2.4.65.2.4.rc15.2.55.2.65.2.6.15.2.6.25.2.6.35.2.75.2.7.15.2.85.2.8.16.0.06.0.0.beta16.0.0.beta26.0.0.beta36.0.0.rc16.0.0.rc26.0.16.0.1.rc16.0.26.0.2.16.0.2.26.0.2.rc16.0.2.rc26.0.36.0.3.16.0.3.26.0.3.36.0.3.46.0.3.5 |
7.2.3.1 |
railsUbuntu:Pro:16.04:LTS |
All versions, plus listed versions 2:4.1.10-12:4.2.5-12:4.2.5.1-12:4.2.5.2-22:4.2.6-12:4.2.6-1ubuntu0.1~esm12:4.2.6-1ubuntu0.1~esm2 |
None known |
Show 7 moreShow less
| Package | Affected | Fixed |
|---|---|---|
railsUbuntu:Pro:18.04:LTS |
All versions, plus listed versions 2:4.2.9-22:4.2.9-42:4.2.10-0ubuntu42:4.2.10-0ubuntu4+esm12:4.2.10-0ubuntu4+esm2 |
None known |
railsUbuntu:Pro:20.04:LTS |
All versions, plus listed versions 2:5.2.2.1+dfsg-1ubuntu12:5.2.3+dfsg-32:5.2.3+dfsg-3ubuntu0.1~esm1 |
None known |
railsUbuntu:Pro:22.04:LTS |
All versions, plus listed versions 2:6.0.3.7+dfsg-22:6.1.4.1+dfsg-8ubuntu22:6.1.4.1+dfsg-8ubuntu2+esm1 |
None known |
railsUbuntu:24.04:LTS |
All versions, plus listed versions 2:6.1.7.3+dfsg-2build12:6.1.7.3+dfsg-3 |
None known |
railsUbuntu:25.10 |
All versions, plus listed versions 2:6.1.7.3+dfsg-72:7.2.2.1+dfsg-7 |
None known |
railsUbuntu:26.10 |
All versions, plus listed versions 2:7.2.3+dfsg-22:7.2.3.2+dfsg-2 |
None known |
railsUbuntu:26.04:LTS |
All versions, plus listed versions 2:7.2.2.1+dfsg-72:7.2.2.2+dfsg-22:7.2.3+dfsg-2 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-33173 is a medium vulnerability (CVSS 5.3) in Rubyonrails Rails, published March 23, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.40%, the 34th percentile. Fixed in activestorage 8.1.2.1.
References
github.com/rails/rails/security/advisories/GHSA-qcfx-2mfw-w4cg
Show 9 moreShow less
nvd.nist.gov/vuln/detail/CVE-2026-33173
security-tracker.debian.org/tracker/CVE-2026-33173
ubuntu.com/security/CVE-2026-33173
cve.org/CVERecord?id=CVE-2026-33173
Left out here: 111 versions. The JSON record has them.