{"id":"CVE-2026-30948","aliases":["BIT-parse-2026-30948","GHSA-hcj7-6gxh-24ww"],"url":"https://o3.security/vulnerability/CVE-2026-30948","summary":"Parse Server has stored cross-site scripting (XSS) via SVG file upload","details":"### Impact\n\nA stored cross-site scripting (XSS) vulnerability allows any authenticated user to upload an SVG file containing JavaScript. The file is served inline with `Content-Type: image/svg+xml` and without protective headers, causing the browser to execute embedded scripts in the Parse Server origin. This can be exploited to steal session tokens from `localStorage` and achieve account takeover.\n\nThe default `fileExtensions` option blocks HTML file extensions but does not block SVG, which is a well-known XSS vector. All Parse Server deployments where file upload is enabled for authenticated users (the default) are affected.\n\n### Patches\n\nThe fix adds `svg` (case-insensitive) to the default file extension denylist. The default regex changes from `^(?![xXsS]?[hH][tT][mM][lL]?$)` to `^(?!([xXsS]?[hH][tT][mM][lL]?|[sS][vV][gG])$)`.\n\n### Workarounds\n\nConfigure the `fileExtensions` option to explicitly block SVG uploads:\n\n```js\n{\n  fileUpload: {\n    fileExtensions: ['^(?!([xXsS]?[hH][tT][mM][lL]?|[sS][vV][gG])$)']\n  }\n}\n```\n\n### References\n\n- GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-hcj7-6gxh-24ww\n- Fix Parse Server 9: https://github.com/parse-community/parse-server/releases/tag/9.5.2-alpha.4\n- Fix Parse Server 8: https://github.com/parse-community/parse-server/releases/tag/8.6.17","published":"2026-03-10T20:18:23.962Z","modified":"2026-08-12T03:51:14.464234926Z","cvss":null,"epss":{"score":0.00216,"percentile":0.12237,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"parse-server","fixedVersion":"9.5.2-alpha.4"},{"ecosystem":"npm","name":"parse-server","fixedVersion":"8.6.17"}],"fix":null,"references":[{"type":"WEB","url":"https://github.com/parse-community/parse-server/releases/tag/8.6.17"},{"type":"WEB","url":"https://github.com/parse-community/parse-server/releases/tag/9.5.2-alpha.4"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/30xxx/CVE-2026-30948.json"},{"type":"ADVISORY","url":"https://github.com/parse-community/parse-server/security/advisories/GHSA-hcj7-6gxh-24ww"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-30948"},{"type":"PACKAGE","url":"https://github.com/parse-community/parse-server"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:14.464234926Z"}}