{"cve":"CVE-2026-63466","nvd":{"published":"2026-08-21T19:17:32.117","modified":"2026-10-14T19:10:00.297","status":"Deferred","description":"Unleash is an open-source feature management platform. Prior to 8.0.3, FeatureEventFormatterMd.format in src/lib/addons/feature-event-formatter-md.ts assigns Mustache.escape to an identity function before rendering action and path templates. Because Mustache.escape is process-wide, the assignment disables escaping for subsequent Mustache.render calls in email-service.ts, webhook.ts, datadog.ts, and new-relic.ts. An editor-level user can place Slack or Microsoft Teams link syntax in an unrestricted username, trigger a feature event, and inject an attacker-labeled link into a trusted outbound notification channel, while other Mustache sinks remain unescaped until restart. This issue is fixed in version 8.0.3.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N","score":4.1},"cwes":["CWE-116"],"references":["https://github.com/Unleash/unleash/commit/002012cfdbedd2e9b7db9dc83b9f549f761db22e","https://github.com/Unleash/unleash/releases/tag/v8.0.3","https://github.com/Unleash/unleash/security/advisories/GHSA-w4mq-xh27-6xpx"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:49:38.260478770+00:00"},"epss":{"cve":"CVE-2026-63466","score":0.00319,"percentile":0.24639,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-w4mq-xh27-6xpx","url":"https://osv.dev/vulnerability/GHSA-w4mq-xh27-6xpx","summary":"Unleash: Global Mustache.escape override disables HTML escaping process-wide, enabling Slack/Teams link-injection via unrestricted username","modified":"2026-08-21T19:40:58.377206Z","packages":[{"ecosystem":"npm","name":"unleash-server","purl":"pkg:npm/unleash-server","ranges":["<8.0.3"],"fixed":["8.0.3"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}