OAuth 1.0 session-fixation chain via unauthenticated provisional-consumer registration and insecure v1_0Allowed default

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-18918
StatePUBLISHED
Assignereclipse
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-28 12:16:27 UTC
Updated2026-09-01 21:11:35 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v4.0 9.1 CRITICAL from [email protected]

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

EPSS: 0.003730000 probability, percentile 0.303910000 (date 2026-09-03)

Problem Types: CWE-863 | CWE-863 CWE-863

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary9.1CRITICALCVSS: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/C...
4.0CNACVSS9.1CRITICALCVSS: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/...

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
None
User Interaction
None
Confidentiality
High
Integrity
High
Availability
None
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Eclipse Foundation Eclipse Lyo affected 2.0.0 7.0.0 custom Not specified

References

ReferenceSourceLinkTags
github.com/eclipse-lyo/lyo/releases/tag/v6.0.1.Final [email protected] github.com
gitlab.eclipse.org/security/cve-assignment/-/work_items/221 [email protected] gitlab.eclipse.org
github.com/eclipse-lyo/lyo/releases/tag/v7.0.0.Beta3 [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Eclipse Foundation Security Team (en)

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