{"id":"CVE-2026-71502","summary":"Unauthenticated Stored Vue Template Injection Leads to Cross-Site Scripting in CTI-Transmute","details":"CTI-Transmute contains a stored cross-site scripting vulnerability caused by insufficient neutralization of Vue template expression delimiters in server-rendered user-controlled data.\n\nAn unauthenticated attacker can create a public conversion whose name or description contains a malicious Vue expression using the application's configured [[ ... ]] delimiters. User profile names may provide an additional injection vector. Although Jinja HTML escaping is applied, the resulting value is subsequently included in a DOM region compiled by Vue.\n\nVue interprets the attacker-controlled value as a template expression rather than ordinary text. By accessing the JavaScript Function constructor from within the expression, an attacker can execute arbitrary JavaScript in the security context of the CTI-Transmute origin. The application's nonce-based Content Security Policy does not prevent exploitation because the Vue runtime compiler requires the unsafe-eval policy exception.\n\nThe malicious payload is stored by the application and executed whenever another user opens an affected page, such as the public conversion detail page. The victim may be a normal user or an administrator. Successful exploitation could allow the attacker to:\n\n  *  Access data available to the victim through the application.\n  *  Extract API keys, tokens, or other sensitive information exposed to the page.\n  *  Perform authenticated actions using the victim's session.\n  *  Modify conversions or other application data.\n  *  Escalate the impact by targeting an administrator.\n\n\nA demonstrated payload can use [].constructor.constructor(...) to obtain the JavaScript Function constructor and execute arbitrary code. The regression tests also show that a short first-stage payload could retrieve an uncapped conversion description and evaluate a larger second-stage payload.\n\nThe patch addresses the vulnerability by registering a global Jinja finalize hook that inserts a zero-width Unicode word joiner inside every Vue delimiter found in server-rendered values. This prevents Vue from recognizing the values as template expressions while preserving their visible representation.","modified":"2026-08-28T11:30:58.108064642Z","published":"2026-08-06T20:30:04.442Z","database_specific":{"cna_assigner":"CIRCL","cwe_ids":["CWE-1336","CWE-79"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/71xxx/CVE-2026-71502.json","unresolved_ranges":[{"source":"AFFECTED_FIELD","extracted_events":[{"last_affected":"1.4.0"}]}]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/71xxx/CVE-2026-71502.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-71502"},{"type":"FIX","url":"https://github.com/MISP/cti-transmute/commit/4f43c9181a00262bec2a6dfbc9ff9c50d534e918"},{"type":"FIX","url":"https://github.com/MISP/cti-transmute/commit/522fa8ff8223b12a6128ea3fc2344a77b7b9108d"},{"type":"FIX","url":"https://github.com/MISP/cti-transmute/commit/ad8bf2b8031491cefb552314ef7ff6f4148ca95a"},{"type":"FIX","url":"https://github.com/MISP/cti-transmute/commit/ecfdaef63860a071c6f07afd30156ca77a77ad2b"},{"type":"PACKAGE","url":"https://github.com/MISP/cti-transmute"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/misp/cti-transmute","events":[{"introduced":"0"},{"fixed":"4f43c9181a00262bec2a6dfbc9ff9c50d534e918"},{"fixed":"522fa8ff8223b12a6128ea3fc2344a77b7b9108d"},{"fixed":"ad8bf2b8031491cefb552314ef7ff6f4148ca95a"},{"fixed":"ecfdaef63860a071c6f07afd30156ca77a77ad2b"}],"database_specific":{"source":"REFERENCES"}}],"versions":["v1.5","v1.4","v1.3"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-71502.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N"}]}