by Kastro
Paper/Archive/CVE-2026-18918

CVE-2026-18918

Eclipse Foundation Eclipse Lyo — OAuth 1.0 session-fixation chain via unauthenticated provisional-consumer registration and insecure v1_0Allowed default

EPSS 0.5%CVSS 9.1
critical.is priorityof 100
36
CVSS 9.1 (CNA)9.1 / 10 × 3027.3Not in CISA KEV+300.0EPSS percentile 43.5.435 × 208.7No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
Eclipse Lyo2.0.0 – < 7.0.07.0.0CNA

Scores by source

eclipse (CNA)9.1CVSS: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
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

refgithub.com/eclipse-lyo/lyo/releases/tag/v6.0.1.Finalrefgithub.com/eclipse-lyo/lyo/releases/tag/v7.0.0.Beta3refgitlab.eclipse.org/security/cve-assignment/-/work_items/221