CVE-2026-33173
Rubyonrails Rails ≤ 7.2.3.1
Raw vector
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:XSummary
CVE-2026-33173 is a medium-severity Improper Verification of Intent by Broadcast Receiver (CWE-925) vulnerability in Rubyonrails Rails. Its CVSS base score is 5.3 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Inter-Process Communication (T1559); ranked at the 32th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and IA-9 (Service Identification and Authentication) — see the control section below for these in your framework.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-14626
Vulnerability Data
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`…
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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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Access enforcement requires the receiver to check authorizations on incoming intents before acting, directly stopping unauthorized sources from succeeding.
Service identification and authentication forces the receiver to verify the sending service or component before accepting the intent.
Information flow enforcement mandates validating the origin of each message before allowing processing, preventing the exact flaw described.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure development practices include explicit sender verification for broadcast receivers.
Verifying sender identity directly prevents unauthorized broadcast Intents.
Verifying identity assertions implements the missing authorization check for received Intents.
Enforcing authorization policy for the receiver mitigates the improper verification flaw.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing can detect missing intent verification but does not prevent the weakness by itself.
Application security requirements can mandate intent verification for broadcast receivers.
Secure architecture principles include proper component authorization and input validation.
Secure coding practices directly address proper intent verification in broadcast receivers.