{"id":"CVE-2025-53479","aliases":["EUVD-2025-20666","GHSA-mjwg-jq5c-p8xr"],"status":"published","title":"CheckUser: Reflected Cross-Site Scripting (XSS) in Special:CheckUser via unsanitized internationalized message","description":"The CheckUser extension’s Special:CheckUser interface is vulnerable to reflected XSS via the rev-deleted-user message. This message is rendered without proper escaping, making it possible to inject JavaScript through the uselang=x-xss language override mechanism.\n\n\n\n\nThis issue affects Mediawiki - CheckUser extension: from 1.42.X before 1.42.7, from 1.43.X before 1.43.2.","severity":{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"adp","from":"cve"},"epss":{"day":"2026-11-10","score":0.00198,"percentile":0.09701,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-79"],"published":"2025-07-08T17:16:36Z","modified":"2026-06-17T09:38:17Z","products":[{"vendor":"the wikimedia foundation","product":"mediawiki - checkuser extension"},{"vendor":"wikimedia foundation","product":"mediawiki - checkuser extension"}],"references":[{"url":"https://phabricator.wikimedia.org/T394693","tags":["exploit"]},{"url":"https://gerrit.wikimedia.org/r/q/I159e14543912cb3bc7f4a00c3090c0285b154786"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2025-53479"},{"url":"https://github.com/advisories/GHSA-mjwg-jq5c-p8xr"}],"sources":{"cve":[{"id":"CVE-2025-53479","title":"CheckUser: Reflected Cross-Site Scripting (XSS) in Special:CheckUser via unsanitized internationalized message","description":"The CheckUser extension’s Special:CheckUser interface is vulnerable to reflected XSS via the rev-deleted-user message. This message is rendered without proper escaping, making it possible to inject JavaScript through the uselang=x-xss language override mechanism.\n\n\n\n\nThis issue affects Mediawiki - CheckUser extension: from 1.42.X before 1.42.7, from 1.43.X before 1.43.2.","status":"published","published":"2025-07-08T17:16:36.081Z","modified":"2025-07-10T13:18:39.505Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"adp"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:32:48.853452Z"}],"euvd":[{"id":"EUVD-2025-20666","description":"The CheckUser extension’s Special:CheckUser interface is vulnerable to reflected XSS via the rev-deleted-user message. This message is rendered without proper escaping, making it possible to inject JavaScript through the uselang=x-xss language override mechanism.\n\n\n\n\nThis issue affects Mediawiki - CheckUser extension: from 1.42.X before 1.42.7, from 1.43.X before 1.43.2.","status":"published","published":"2025-07-08T17:16:36Z","modified":"2025-07-10T13:18:39Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T20:32:10.118111Z"}],"ghsa":[{"id":"GHSA-mjwg-jq5c-p8xr","title":"The CheckUser extension’s Special:CheckUser interface is vulnerable to reflected XSS via the rev...","description":"The CheckUser extension’s Special:CheckUser interface is vulnerable to reflected XSS via the rev-deleted-user message. This message is rendered without proper escaping, making it possible to inject JavaScript through the uselang=x-xss language override mechanism.\n\n\n\n\nThis issue affects Mediawiki - CheckUser extension: from 1.39.X before 1.39.13, from 1.42.X before 1.42.7, from 1.43.X before 1.43.2.","status":"published","published":"2025-07-08T18:31:52Z","modified":"2025-07-10T15:32:21Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:02:58.788337Z"}],"nvd":[{"id":"CVE-2025-53479","description":"The CheckUser extension’s Special:CheckUser interface is vulnerable to reflected XSS via the rev-deleted-user message. This message is rendered without proper escaping, making it possible to inject JavaScript through the uselang=x-xss language override mechanism.\n\n\n\n\nThis issue affects Mediawiki - CheckUser extension: from 1.42.X before 1.42.7, from 1.43.X before 1.43.2.","status":"published","published":"2025-07-08T18:15:40.387Z","modified":"2026-06-17T09:38:17.057Z","cvss":[{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:11:17.727956Z"}]}}