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.
CVE-2026-33173
MEDIUMNVD 5.35.3
EchelonGraph scoreLOW confidence
This medium-severity CVE scores 5.3 under NVD CVSS v3. EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: nvd
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.3Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 5.3
- EG Score
- 5.3(low)
- EG Risk
- 28(Track)EG Risk 28/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity53% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 32%
- KEV
- Not listed
Published
March 24, 2026
Last Modified
June 17, 2026
References (7)
- security-advisories@githubhttps://github.com/rails/rails/commit/707c0f1f41f067fdf96d54e99d43b28dfaae7e53
- security-advisories@githubhttps://github.com/rails/rails/commit/8fcb934caadc79c8cc4ce53287046d0f67005b3e
- security-advisories@githubhttps://github.com/rails/rails/commit/d9502f5214e2198245a4c1defe9cd02a7c8057d0
- security-advisories@githubhttps://github.com/rails/rails/releases/tag/v7.2.3.1
- security-advisories@githubhttps://github.com/rails/rails/releases/tag/v8.0.4.1
- security-advisories@githubhttps://github.com/rails/rails/releases/tag/v8.1.2.1
- security-advisories@githubhttps://github.com/rails/rails/security/advisories/GHSA-qcfx-2mfw-w4cg
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 4× in last 7d / 4× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-08-01 04:16 UTCEPSS rescore
- 2026-07-30 16:28 UTCEPSS rescore
- 2026-07-30 01:30 UTCEPSS rescore
- 2026-07-27 14:31 UTCEG score recompute
Frequently asked(5)
What is CVE-2026-33173?
CVE-2026-33173 is a medium vulnerability published on March 24, 2026. 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…
When was CVE-2026-33173 disclosed?
CVE-2026-33173 was first published in the National Vulnerability Database on March 24, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-33173 actively exploited?
CVE-2026-33173 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 68.2% of all scored CVEs.
What is the CVSS score of CVE-2026-33173?
CVE-2026-33173 has a CVSS v3 base score of 5.3 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-33173?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-33173, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-33173
Is Your Infrastructure Affected by CVE-2026-33173?
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