CVE-2026-18918 (GCVE-0-2026-18918)
Vulnerability from cvelistv5 – Published: 2026-08-28 08:54 – Updated: 2026-08-31 12:27
VLAI
EPSS
VEX
Title
OAuth 1.0 session-fixation chain via unauthenticated provisional-consumer registration and insecure v1_0Allowed default
Summary
In Eclipse Lyo versions 2.0.0 to 7.0.0, OAuth server authorization checks can be bypassed when the 2-legged auth is supported by the server. In those cases, application that based their authz filters upon Lyo-provided `AbstractAdapterCredentialsFilter`, are vulnerable. An attacked can create a provisional trusted client (valid use-case) but then it can be used as a trusted client immediately without requiring the administrator approval to clear the provisional status. The 3-legged path requiring user interaction is not vulnerable and rejects provisional clients.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-28 15:03 UTC
CWE
Assigner
References
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Eclipse Foundation | Eclipse Lyo |
Affected:
2.0.0 , < 7.0.0
(custom)
|
guessed |
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-18918",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "yes"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-08-28T15:03:52.629478Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-08-28T15:04:16.704Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Eclipse Lyo",
"vendor": "Eclipse Foundation",
"versions": [
{
"lessThan": "7.0.0",
"status": "affected",
"version": "2.0.0",
"versionType": "custom"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "Eclipse Foundation Security Team"
}
],
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "\u003cp\u003eIn Eclipse Lyo versions 2.0.0 to 7.0.0, OAuth server authorization checks can be bypassed when the 2-legged auth is supported by the server. In those cases, application that based their authz filters upon Lyo-provided `AbstractAdapterCredentialsFilter`, are vulnerable. An attacked can create a provisional trusted client (valid use-case) but then it can be used as a trusted client immediately without requiring the administrator approval to clear the provisional status. The 3-legged path requiring user interaction is not vulnerable and rejects provisional clients.\u003c/p\u003e"
}
],
"value": "In Eclipse Lyo versions 2.0.0 to 7.0.0, OAuth server authorization checks can be bypassed when the 2-legged auth is supported by the server. In those cases, application that based their authz filters upon Lyo-provided `AbstractAdapterCredentialsFilter`, are vulnerable. An attacked can create a provisional trusted client (valid use-case) but then it can be used as a trusted client immediately without requiring the administrator approval to clear the provisional status. The 3-legged path requiring user interaction is not vulnerable and rejects provisional clients."
}
],
"impacts": [
{
"capecId": "CAPEC-114",
"descriptions": [
{
"lang": "en",
"value": "CAPEC-114"
}
]
}
],
"metrics": [
{
"cvssV4_0": {
"Automatable": "YES",
"Recovery": "USER",
"Safety": "NOT_DEFINED",
"attackComplexity": "LOW",
"attackRequirements": "PRESENT",
"attackVector": "NETWORK",
"baseScore": 9.1,
"baseSeverity": "CRITICAL",
"exploitMaturity": "NOT_DEFINED",
"privilegesRequired": "NONE",
"providerUrgency": "RED",
"subAvailabilityImpact": "NONE",
"subConfidentialityImpact": "NONE",
"subIntegrityImpact": "NONE",
"userInteraction": "NONE",
"valueDensity": "CONCENTRATED",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/AU:Y/R:U/V:C/RE:L/U:Red",
"version": "4.0",
"vulnAvailabilityImpact": "NONE",
"vulnConfidentialityImpact": "HIGH",
"vulnIntegrityImpact": "HIGH",
"vulnerabilityResponseEffort": "LOW"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-863",
"description": "CWE-863",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-31T12:27:40.249Z",
"orgId": "e51fbebd-6053-4e49-959f-1b94eeb69a2c",
"shortName": "eclipse"
},
"references": [
{
"url": "https://github.com/eclipse-lyo/lyo/releases/tag/v6.0.1.Final"
},
{
"url": "https://github.com/eclipse-lyo/lyo/releases/tag/v7.0.0.Beta3"
},
{
"url": "https://gitlab.eclipse.org/security/cve-assignment/-/work_items/221"
}
],
"source": {
"discovery": "INTERNAL"
},
"title": "OAuth 1.0 session-fixation chain via unauthenticated provisional-consumer registration and insecure v1_0Allowed default",
"x_generator": {
"engine": "Vulnogram 1.0.5"
}
}
},
"cveMetadata": {
"assignerOrgId": "e51fbebd-6053-4e49-959f-1b94eeb69a2c",
"assignerShortName": "eclipse",
"cveId": "CVE-2026-18918",
"datePublished": "2026-08-28T08:54:07.990Z",
"dateReserved": "2026-08-05T07:44:04.388Z",
"dateUpdated": "2026-08-31T12:27:40.249Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-18918",
"date": "2026-10-16",
"epss": "0.00373",
"percentile": "0.29725"
},
"nvd": {
"cve": {
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Eclipse Lyo",
"vendor": "Eclipse Foundation",
"versions": [
{
"lessThan": "7.0.0",
"status": "affected",
"version": "2.0.0",
"versionType": "custom"
}
]
}
],
"source": "emo@eclipse.org"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In Eclipse Lyo versions 2.0.0 to 7.0.0, OAuth server authorization checks can be bypassed when the 2-legged auth is supported by the server. In those cases, application that based their authz filters upon Lyo-provided `AbstractAdapterCredentialsFilter`, are vulnerable. An attacked can create a provisional trusted client (valid use-case) but then it can be used as a trusted client immediately without requiring the administrator approval to clear the provisional status. The 3-legged path requiring user interaction is not vulnerable and rejects provisional clients."
}
],
"id": "CVE-2026-18918",
"lastModified": "2026-09-01T21:11:35.983",
"metrics": {
"cvssMetricV40": [
{
"cvssData": {
"Automatable": "YES",
"Recovery": "USER",
"Safety": "NOT_DEFINED",
"attackComplexity": "LOW",
"attackRequirements": "PRESENT",
"attackVector": "NETWORK",
"availabilityRequirement": "NOT_DEFINED",
"baseScore": 9.1,
"baseSeverity": "CRITICAL",
"confidentialityRequirement": "NOT_DEFINED",
"exploitMaturity": "NOT_DEFINED",
"integrityRequirement": "NOT_DEFINED",
"modifiedAttackComplexity": "NOT_DEFINED",
"modifiedAttackRequirements": "NOT_DEFINED",
"modifiedAttackVector": "NOT_DEFINED",
"modifiedPrivilegesRequired": "NOT_DEFINED",
"modifiedSubAvailabilityImpact": "NOT_DEFINED",
"modifiedSubConfidentialityImpact": "NOT_DEFINED",
"modifiedSubIntegrityImpact": "NOT_DEFINED",
"modifiedUserInteraction": "NOT_DEFINED",
"modifiedVulnAvailabilityImpact": "NOT_DEFINED",
"modifiedVulnConfidentialityImpact": "NOT_DEFINED",
"modifiedVulnIntegrityImpact": "NOT_DEFINED",
"privilegesRequired": "NONE",
"providerUrgency": "RED",
"subAvailabilityImpact": "NONE",
"subConfidentialityImpact": "NONE",
"subIntegrityImpact": "NONE",
"userInteraction": "NONE",
"valueDensity": "CONCENTRATED",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/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:Y/R:U/V:C/RE:L/U:Red",
"version": "4.0",
"vulnAvailabilityImpact": "NONE",
"vulnConfidentialityImpact": "HIGH",
"vulnIntegrityImpact": "HIGH",
"vulnerabilityResponseEffort": "LOW"
},
"source": "emo@eclipse.org",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-18918",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-08-28T15:03:52.629478Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-08-28T12:16:27.150",
"references": [
{
"source": "emo@eclipse.org",
"url": "https://github.com/eclipse-lyo/lyo/releases/tag/v6.0.1.Final"
},
{
"source": "emo@eclipse.org",
"url": "https://github.com/eclipse-lyo/lyo/releases/tag/v7.0.0.Beta3"
},
{
"source": "emo@eclipse.org",
"url": "https://gitlab.eclipse.org/security/cve-assignment/-/work_items/221"
}
],
"sourceIdentifier": "emo@eclipse.org",
"vulnStatus": "Deferred",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-863"
}
],
"source": "emo@eclipse.org",
"type": "Secondary"
}
]
}
},
"vulnrichment": {
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-18918",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "yes"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-08-28T15:03:52.629478Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-08-28T15:04:10.782Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Eclipse Lyo",
"vendor": "Eclipse Foundation",
"versions": [
{
"lessThan": "7.0.0",
"status": "affected",
"version": "2.0.0",
"versionType": "custom"
}
]
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "Eclipse Foundation Security Team"
}
],
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "\u003cp\u003eIn Eclipse Lyo versions 2.0.0 to 7.0.0, OAuth server authorization checks can be bypassed when the 2-legged auth is supported by the server. In those cases, application that based their authz filters upon Lyo-provided `AbstractAdapterCredentialsFilter`, are vulnerable. An attacked can create a provisional trusted client (valid use-case) but then it can be used as a trusted client immediately without requiring the administrator approval to clear the provisional status. The 3-legged path requiring user interaction is not vulnerable and rejects provisional clients.\u003c/p\u003e"
}
],
"value": "In Eclipse Lyo versions 2.0.0 to 7.0.0, OAuth server authorization checks can be bypassed when the 2-legged auth is supported by the server. In those cases, application that based their authz filters upon Lyo-provided `AbstractAdapterCredentialsFilter`, are vulnerable. An attacked can create a provisional trusted client (valid use-case) but then it can be used as a trusted client immediately without requiring the administrator approval to clear the provisional status. The 3-legged path requiring user interaction is not vulnerable and rejects provisional clients."
}
],
"impacts": [
{
"capecId": "CAPEC-114",
"descriptions": [
{
"lang": "en",
"value": "CAPEC-114"
}
]
}
],
"metrics": [
{
"cvssV4_0": {
"Automatable": "YES",
"Recovery": "USER",
"Safety": "NOT_DEFINED",
"attackComplexity": "LOW",
"attackRequirements": "PRESENT",
"attackVector": "NETWORK",
"baseScore": 9.1,
"baseSeverity": "CRITICAL",
"exploitMaturity": "NOT_DEFINED",
"privilegesRequired": "NONE",
"providerUrgency": "RED",
"subAvailabilityImpact": "NONE",
"subConfidentialityImpact": "NONE",
"subIntegrityImpact": "NONE",
"userInteraction": "NONE",
"valueDensity": "CONCENTRATED",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/AU:Y/R:U/V:C/RE:L/U:Red",
"version": "4.0",
"vulnAvailabilityImpact": "NONE",
"vulnConfidentialityImpact": "HIGH",
"vulnIntegrityImpact": "HIGH",
"vulnerabilityResponseEffort": "LOW"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-863",
"description": "CWE-863",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-31T12:27:40.249Z",
"orgId": "e51fbebd-6053-4e49-959f-1b94eeb69a2c",
"shortName": "eclipse"
},
"references": [
{
"url": "https://github.com/eclipse-lyo/lyo/releases/tag/v6.0.1.Final"
},
{
"url": "https://github.com/eclipse-lyo/lyo/releases/tag/v7.0.0.Beta3"
},
{
"url": "https://gitlab.eclipse.org/security/cve-assignment/-/work_items/221"
}
],
"source": {
"discovery": "INTERNAL"
},
"title": "OAuth 1.0 session-fixation chain via unauthenticated provisional-consumer registration and insecure v1_0Allowed default",
"x_generator": {
"engine": "Vulnogram 1.0.5"
}
}
},
"cveMetadata": {
"assignerOrgId": "e51fbebd-6053-4e49-959f-1b94eeb69a2c",
"assignerShortName": "eclipse",
"cveId": "CVE-2026-18918",
"datePublished": "2026-08-28T08:54:07.990Z",
"dateReserved": "2026-08-05T07:44:04.388Z",
"dateUpdated": "2026-08-31T12:27:40.249Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
Loading…
Loading…
Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.
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.
Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
Loading timeline…
Loading…
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.