{"id":"CVE-2026-90882","state":"PUBLISHED","title":"Reflected arbitrary origins with credentials, allowing cross-origin reads of authenticated user data","description":"The open-vsx.org deployment returned Access-Control-Allow-Origin reflecting the requesting origin together with Access-Control-Allow-Credentials: true on the authenticated /user/ endpoints. A page on any origin could therefore issue credentialed requests to the service in a logged-in user's browser and read the responses.\n\n\n\nThis exposed /user (login name, avatar, homepage, tokens URL), /user/tokens, /user/namespaces, /user/extensions, /user/search/{name} and /user/namespace/{name}/members, and — because /user/csrf was readable the same way — allowed the CSRF protection on write endpoints to be defeated. Chaining the two, an attacker page could call /user/token/create and exfiltrate a personal access token carrying publish and delete rights over the victim's namespaces.\n\n\n\nThe headers were emitted by the CDN/edge layer, not by the application: the Open VSX software sets allowCredentials(true) in exactly one place, against a single exact origin derived from ovsx.webui.url, and defines no CORS mapping on /user/ beyond it. No configuration of the software produces origin reflection with credentials.","publishedAt":"2026-09-22T09:27:34.713Z","updatedAt":"2026-09-22T13:06:14.742Z","severity":{"score":8.7,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","source":"eclipse"},"assigner":"eclipse","products":["Eclipse Foundation open-vsx.org"],"affected":[{"vendor":"Eclipse Foundation","product":"open-vsx.org","defaultStatus":"unaffected","versions":[{"version":"29/04/2026","status":"affected","lessThanOrEqual":"07/09/2026","versionType":"custom"}]}],"references":["https://gitlab.eclipse.org/security/cve-assignment/-/work_items/289"],"weaknesses":["CWE-942"],"ingestedAt":"2026-10-29T20:13:34.582Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/90xxx/CVE-2026-90882.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90882","state":"PUBLISHED","datePublished":"2026-09-22T09:27:34.713Z","dateUpdated":"2026-09-22T13:06:14.742Z","assignerShortName":"eclipse","assignerOrgId":"e51fbebd-6053-4e49-959f-1b94eeb69a2c","dateReserved":"2026-09-14T07:44:22.377Z"},"containers":{"cna":{"title":"Reflected arbitrary origins with credentials, allowing cross-origin reads of authenticated user data","descriptions":[{"lang":"en","value":"The open-vsx.org deployment returned Access-Control-Allow-Origin reflecting the requesting origin together with Access-Control-Allow-Credentials: true on the authenticated /user/ endpoints. A page on any origin could therefore issue credentialed requests to the service in a logged-in user's browser and read the responses.\n\n\n\nThis exposed /user (login name, avatar, homepage, tokens URL), /user/tokens, /user/namespaces, /user/extensions, /user/search/{name} and /user/namespace/{name}/members, and — because /user/csrf was readable the same way — allowed the CSRF protection on write endpoints to be defeated. Chaining the two, an attacker page could call /user/token/create and exfiltrate a personal access token carrying publish and delete rights over the victim's namespaces.\n\n\n\nThe headers were emitted by the CDN/edge layer, not by the application: the Open VSX software sets allowCredentials(true) in exactly one place, against a single exact origin derived from ovsx.webui.url, and defines no CORS mapping on /user/ beyond it. No configuration of the software produces origin reflection with credentials."}],"affected":[{"vendor":"Eclipse Foundation","product":"open-vsx.org","defaultStatus":"unaffected","versions":[{"version":"29/04/2026","status":"affected","lessThanOrEqual":"07/09/2026","versionType":"custom"}]}],"references":[{"url":"https://gitlab.eclipse.org/security/cve-assignment/-/work_items/289"}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"PASSIVE","vulnConfidentialityImpact":"HIGH","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"HIGH","subIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED","version":"4.0","baseSeverity":"HIGH","baseScore":8.7,"vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-942","lang":"en","description":"CWE-942","type":"CWE"}]}],"providerMetadata":{"shortName":"eclipse","orgId":"e51fbebd-6053-4e49-959f-1b94eeb69a2c","dateUpdated":"2026-09-22T09:27:34.713Z"},"credits":[{"lang":"en","value":"https://github.com/Char0n1507","type":"finder"}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"Vulnogram 1.0.5"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-22T13:06:04.901059Z","id":"CVE-2026-90882","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-22T13:06:14.742Z"}}]}}}