{"id":"CVE-2026-18756","summary":"HumHub Community Edition 1.18.4-pl1 - Reflected XSS in Space membership request button rendering","details":"HumHub Community Edition 1.18.4 contains a reflected cross-site scripting vulnerability in the Space membership-request workflow. An attacker can place attacker-controlled button configuration in the options query-string parameter of space/membership/request-membership-form, lure an authenticated non-member into submitting the legitimate membership request form, and cause the server to return JavaScript containing attacker-controlled code.","modified":"2026-08-30T03:31:05.941835717Z","published":"2026-08-19T14:46:25.019Z","database_specific":{"cna_assigner":"Fluid Attacks","cwe_ids":["CWE-79"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/18xxx/CVE-2026-18756.json"},"references":[{"type":"ADVISORY","url":"https://fluidattacks.com/es/advisories/turizo"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/18xxx/CVE-2026-18756.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-18756"},{"type":"FIX","url":"https://github.com/humhub/humhub/pull/8381"},{"type":"PACKAGE","url":"https://github.com/humhub/humhub"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/humhub/humhub","events":[{"introduced":"3320c4140371b62d8694eeaf943e606d902f007a"},{"last_affected":"3320c4140371b62d8694eeaf943e606d902f007a"}],"database_specific":{"source":"AFFECTED_FIELD","extracted_events":[{"introduced":"1.18.4"},{"last_affected":"1.18.4"}]}}],"versions":["1.18.4","v1.18.4"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-18756.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:N/SC:L/SI:L/SA:N"}]}