CVE-2026-85184 (GCVE-0-2026-85184)
Vulnerability from cvelistv5 – Published: 2026-09-04 09:15 – Updated: 2026-09-04 19:36
VLAI
EPSS
VEX
Title
@fastify/middie vulnerable to path-scoped middleware bypass via absolute-form request target
Summary
@fastify/middie versions >= 9.1.0 and before 9.3.4 decide whether to run path-scoped middleware by matching against the raw request target, while the Fastify router resolves an absolute-form request target to its path before dispatching. Because the two layers evaluate different strings, a request using an absolute-form target reaches the route handler while the path-scoped middleware, such as authentication or authorization, is skipped. An unauthenticated network attacker can use this to bypass path-based access controls in a Fastify application that relies on middie for those controls. Users should upgrade to @fastify/middie 9.3.4 or later.
Severity
9.1 (Critical)
SSVC
Exploitation: none
Automatable: yes
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-04 19:36 UTC
CWE
- CWE-436 - Interpretation Conflict
Assigner
References
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| @fastify/middie | @fastify/middie |
Affected:
9.1.0 , < 9.3.4
(semver)
Unaffected: 9.3.4 (semver) |
guessed |
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-85184",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "yes"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-09-04T19:36:12.098740Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-09-04T19:36:20.968Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"packageURL": "pkg:npm/@fastify/middie",
"product": "@fastify/middie",
"vendor": "@fastify/middie",
"versions": [
{
"lessThan": "9.3.4",
"status": "affected",
"version": "9.1.0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "9.3.4",
"versionType": "semver"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "reporter",
"value": "zer0d4y5"
},
{
"lang": "en",
"type": "remediation developer",
"value": "mcollina"
},
{
"lang": "en",
"type": "remediation reviewer",
"value": "UlisesGascon"
}
],
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "@fastify/middie versions \u003e= 9.1.0 and before 9.3.4 decide whether to run path-scoped middleware by matching against the raw request target, while the Fastify router resolves an absolute-form request target to its path before dispatching. Because the two layers evaluate different strings, a request using an absolute-form target reaches the route handler while the path-scoped middleware, such as authentication or authorization, is skipped. An unauthenticated network attacker can use this to bypass path-based access controls in a Fastify application that relies on middie for those controls. Users should upgrade to @fastify/middie 9.3.4 or later."
}
],
"value": "@fastify/middie versions \u003e= 9.1.0 and before 9.3.4 decide whether to run path-scoped middleware by matching against the raw request target, while the Fastify router resolves an absolute-form request target to its path before dispatching. Because the two layers evaluate different strings, a request using an absolute-form target reaches the route handler while the path-scoped middleware, such as authentication or authorization, is skipped. An unauthenticated network attacker can use this to bypass path-based access controls in a Fastify application that relies on middie for those controls. Users should upgrade to @fastify/middie 9.3.4 or later."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 9.1,
"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-436",
"description": "CWE-436: Interpretation Conflict",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-09-04T09:15:51.216Z",
"orgId": "ce714d77-add3-4f53-aff5-83d477b104bb",
"shortName": "openjs"
},
"references": [
{
"url": "https://github.com/fastify/middie/security/advisories/GHSA-hx87-8wv7-pjv8"
},
{
"url": "https://cna.openjsf.org/security-advisories.html"
}
],
"title": "@fastify/middie vulnerable to path-scoped middleware bypass via absolute-form request target",
"x_generator": {
"engine": "cve-kit 1.0.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "ce714d77-add3-4f53-aff5-83d477b104bb",
"assignerShortName": "openjs",
"cveId": "CVE-2026-85184",
"datePublished": "2026-09-04T09:15:51.216Z",
"dateReserved": "2026-09-03T11:39:08.481Z",
"dateUpdated": "2026-09-04T19:36:20.968Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-85184",
"date": "2026-09-21",
"epss": "0.00316",
"percentile": "0.24647"
},
"nvd": {
"cve": {
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"packageURL": "pkg:npm/@fastify/middie",
"product": "@fastify/middie",
"vendor": "@fastify/middie",
"versions": [
{
"lessThan": "9.3.4",
"status": "affected",
"version": "9.1.0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "9.3.4",
"versionType": "semver"
}
]
}
],
"source": "ce714d77-add3-4f53-aff5-83d477b104bb"
}
],
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:fastify:fastify\\/middie:*:*:*:*:*:node.js:*:*",
"matchCriteriaId": "3CE5045A-6E76-47EB-887B-7890AA2F87B5",
"versionEndExcluding": "9.3.4",
"versionStartIncluding": "9.1.0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "@fastify/middie versions \u003e= 9.1.0 and before 9.3.4 decide whether to run path-scoped middleware by matching against the raw request target, while the Fastify router resolves an absolute-form request target to its path before dispatching. Because the two layers evaluate different strings, a request using an absolute-form target reaches the route handler while the path-scoped middleware, such as authentication or authorization, is skipped. An unauthenticated network attacker can use this to bypass path-based access controls in a Fastify application that relies on middie for those controls. Users should upgrade to @fastify/middie 9.3.4 or later."
}
],
"id": "CVE-2026-85184",
"lastModified": "2026-09-15T20:02:28.677",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 9.1,
"baseSeverity": "CRITICAL",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
"version": "3.1"
},
"exploitabilityScore": 3.9,
"impactScore": 5.2,
"source": "ce714d77-add3-4f53-aff5-83d477b104bb",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-85184",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-09-04T19:36:12.098740Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-09-04T10:17:13.900",
"references": [
{
"source": "ce714d77-add3-4f53-aff5-83d477b104bb",
"tags": [
"Third Party Advisory"
],
"url": "https://cna.openjsf.org/security-advisories.html"
},
{
"source": "ce714d77-add3-4f53-aff5-83d477b104bb",
"tags": [
"Mitigation",
"Vendor Advisory"
],
"url": "https://github.com/fastify/middie/security/advisories/GHSA-hx87-8wv7-pjv8"
}
],
"sourceIdentifier": "ce714d77-add3-4f53-aff5-83d477b104bb",
"vulnStatus": "Analyzed",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-436"
}
],
"source": "ce714d77-add3-4f53-aff5-83d477b104bb",
"type": "Secondary"
}
]
}
},
"vulnrichment": {
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-85184",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "yes"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-09-04T19:36:12.098740Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-09-04T19:36:17.234Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"packageURL": "pkg:npm/@fastify/middie",
"product": "@fastify/middie",
"vendor": "@fastify/middie",
"versions": [
{
"lessThan": "9.3.4",
"status": "affected",
"version": "9.1.0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "9.3.4",
"versionType": "semver"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "reporter",
"value": "zer0d4y5"
},
{
"lang": "en",
"type": "remediation developer",
"value": "mcollina"
},
{
"lang": "en",
"type": "remediation reviewer",
"value": "UlisesGascon"
}
],
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "@fastify/middie versions \u003e= 9.1.0 and before 9.3.4 decide whether to run path-scoped middleware by matching against the raw request target, while the Fastify router resolves an absolute-form request target to its path before dispatching. Because the two layers evaluate different strings, a request using an absolute-form target reaches the route handler while the path-scoped middleware, such as authentication or authorization, is skipped. An unauthenticated network attacker can use this to bypass path-based access controls in a Fastify application that relies on middie for those controls. Users should upgrade to @fastify/middie 9.3.4 or later."
}
],
"value": "@fastify/middie versions \u003e= 9.1.0 and before 9.3.4 decide whether to run path-scoped middleware by matching against the raw request target, while the Fastify router resolves an absolute-form request target to its path before dispatching. Because the two layers evaluate different strings, a request using an absolute-form target reaches the route handler while the path-scoped middleware, such as authentication or authorization, is skipped. An unauthenticated network attacker can use this to bypass path-based access controls in a Fastify application that relies on middie for those controls. Users should upgrade to @fastify/middie 9.3.4 or later."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 9.1,
"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-436",
"description": "CWE-436: Interpretation Conflict",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-09-04T09:15:51.216Z",
"orgId": "ce714d77-add3-4f53-aff5-83d477b104bb",
"shortName": "openjs"
},
"references": [
{
"url": "https://github.com/fastify/middie/security/advisories/GHSA-hx87-8wv7-pjv8"
},
{
"url": "https://cna.openjsf.org/security-advisories.html"
}
],
"title": "@fastify/middie vulnerable to path-scoped middleware bypass via absolute-form request target",
"x_generator": {
"engine": "cve-kit 1.0.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "ce714d77-add3-4f53-aff5-83d477b104bb",
"assignerShortName": "openjs",
"cveId": "CVE-2026-85184",
"datePublished": "2026-09-04T09:15:51.216Z",
"dateReserved": "2026-09-03T11:39:08.481Z",
"dateUpdated": "2026-09-04T19:36:20.968Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
Loading…
Loading…
Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Loading…
The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Loading…
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
Loading…