CVE-2026-33433
Estado: ModificadaMedia (5.1)—
Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.42, 3.6.11, and 3.7.0-ea.3, when `headerField` is configured with a non-canonical HTTP header name (e.g., `x-auth-user` instead of `X-Auth-User`), an authenticated attacker can inject their own canonical version of that header to impersonate any identity to the backend. The backend receives two header entries — the attacker-injected canonical one is read first, overriding Traefik's non-canonical write. Versions 2.11.42, 3.6.11, and 3.7.0-ea.3 patch the issue.
CVSS
- Versión: 4.0
- Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/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
- Puntuación base: 5.1
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.56%
- Percentil entre todas las CVEs puntuadas: 45
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
CWE
- CWE-290
- CWE-290
Referencias
- https://github.com/traefik/traefik/releases/tag/v2.11.42
- https://github.com/traefik/traefik/releases/tag/v3.6.11
- https://github.com/traefik/traefik/releases/tag/v3.7.0-ea.3
- https://github.com/traefik/traefik/security/advisories/GHSA-qr99-7898-vr7c
- https://access.redhat.com/errata/RHSA-2026:10175
- https://access.redhat.com/security/cve/CVE-2026-33433
- https://bugzilla.redhat.com/show_bug.cgi?id=2452289
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33433.json
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-33433",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-33433",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2026-03-30T12:00:28.784939Z"
}
}
],
"cvssMetricV31": [
{
"type": "Primary",
"source": "nvd@nist.gov",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 8.8,
"attackVector": "NETWORK",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"integrityImpact": "HIGH",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "LOW",
"confidentialityImpact": "HIGH"
},
"impactScore": 5.9,
"exploitabilityScore": 2.8
},
{
"type": "Secondary",
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"cvssData": {
"scope": "CHANGED",
"version": "3.1",
"baseScore": 7.7,
"attackVector": "NETWORK",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:N",
"integrityImpact": "HIGH",
"userInteraction": "NONE",
"attackComplexity": "HIGH",
"availabilityImpact": "NONE",
"privilegesRequired": "HIGH",
"confidentialityImpact": "HIGH"
},
"impactScore": 5.8,
"exploitabilityScore": 1.3
}
],
"cvssMetricV40": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"cvssData": {
"Safety": "NOT_DEFINED",
"version": "4.0",
"Recovery": "NOT_DEFINED",
"baseScore": 5.1,
"Automatable": "NOT_DEFINED",
"attackVector": "NETWORK",
"baseSeverity": "MEDIUM",
"valueDensity": "NOT_DEFINED",
"vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/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",
"exploitMaturity": "NOT_DEFINED",
"providerUrgency": "NOT_DEFINED",
"userInteraction": "NONE",
"attackComplexity": "HIGH",
"attackRequirements": "PRESENT",
"privilegesRequired": "HIGH",
"subIntegrityImpact": "HIGH",
"vulnIntegrityImpact": "NONE",
"integrityRequirement": "NOT_DEFINED",
"modifiedAttackVector": "NOT_DEFINED",
"subAvailabilityImpact": "NONE",
"vulnAvailabilityImpact": "NONE",
"availabilityRequirement": "NOT_DEFINED",
"modifiedUserInteraction": "NOT_DEFINED",
"modifiedAttackComplexity": "NOT_DEFINED",
"subConfidentialityImpact": "HIGH",
"vulnConfidentialityImpact": "NONE",
"confidentialityRequirement": "NOT_DEFINED",
"modifiedAttackRequirements": "NOT_DEFINED",
"modifiedPrivilegesRequired": "NOT_DEFINED",
"modifiedSubIntegrityImpact": "NOT_DEFINED",
"modifiedVulnIntegrityImpact": "NOT_DEFINED",
"vulnerabilityResponseEffort": "NOT_DEFINED",
"modifiedSubAvailabilityImpact": "NOT_DEFINED",
"modifiedVulnAvailabilityImpact": "NOT_DEFINED",
"modifiedSubConfidentialityImpact": "NOT_DEFINED",
"modifiedVulnConfidentialityImpact": "NOT_DEFINED"
}
}
]
},
"affected": [
{
"source": "security-advisories@github.com",
"affectedData": [
{
"vendor": "traefik",
"product": "traefik",
"versions": [
{
"status": "affected",
"version": "< 2.11.42"
},
{
"status": "affected",
"version": ">= 3.0.0-beta1, < 3.6.11"
},
{
"status": "affected",
"version": ">= 3.7.0-ea.1, < 3.7.0-ea.3"
}
]
}
]
},
{
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"affectedData": [
{
"cpes": [
"cpe:/a:redhat:openshift_devspaces:3.27::el9"
],
"vendor": "Red Hat",
"product": "Red Hat OpenShift Dev Spaces 3.27",
"versions": [
{
"status": "unaffected",
"version": "1776718585",
"lessThan": "*",
"versionType": "rpm"
}
],
"packageName": "devspaces/traefik-rhel9",
"collectionURL": "https://catalog.redhat.com/software/containers/",
"defaultStatus": "affected"
}
]
}
],
"published": "2026-03-27T15:16:54.980",
"references": [
{
"url": "https://github.com/traefik/traefik/releases/tag/v2.11.42",
"tags": [
"Product",
"Release Notes"
],
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/traefik/traefik/releases/tag/v3.6.11",
"tags": [
"Product",
"Release Notes"
],
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/traefik/traefik/releases/tag/v3.7.0-ea.3",
"tags": [
"Product",
"Release Notes"
],
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/traefik/traefik/security/advisories/GHSA-qr99-7898-vr7c",
"tags": [
"Exploit",
"Patch",
"Vendor Advisory"
],
"source": "security-advisories@github.com"
},
{
"url": "https://access.redhat.com/errata/RHSA-2026:10175",
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"
},
{
"url": "https://access.redhat.com/security/cve/CVE-2026-33433",
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"
},
{
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2452289",
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"
},
{
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33433.json",
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"
}
],
"vulnStatus": "Modified",
"weaknesses": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"description": [
{
"lang": "en",
"value": "CWE-290"
}
]
},
{
"type": "Secondary",
"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"description": [
{
"lang": "en",
"value": "CWE-290"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.42, 3.6.11, and 3.7.0-ea.3, when `headerField` is configured with a non-canonical HTTP header name (e.g., `x-auth-user` instead of `X-Auth-User`), an authenticated attacker can inject their own canonical version of that header to impersonate any identity to the backend. The backend receives two header entries — the attacker-injected canonical one is read first, overriding Traefik's non-canonical write. Versions 2.11.42, 3.6.11, and 3.7.0-ea.3 patch the issue."
}
],
"lastModified": "2026-07-15T02:20:13.380",
"configurations": [
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "EDF93D3C-490C-4EC6-A934-8B877C389491",
"versionEndExcluding": "2.11.42"
},
{
"criteria": "cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "5CDD2F75-D51B-4443-B0B6-4ED956ADE494",
"versionEndExcluding": "3.6.12",
"versionStartIncluding": "3.0.0"
},
{
"criteria": "cpe:2.3:a:traefik:traefik:3.7.0:ea1:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "7881B288-5141-4508-AB71-3F7586168437"
},
{
"criteria": "cpe:2.3:a:traefik:traefik:3.7.0:ea2:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "AE5788A2-CCF9-4E87-8B94-133874F99CAE"
}
],
"operator": "OR"
}
]
}
],
"sourceIdentifier": "security-advisories@github.com"
}