{"id":"CVE-2021-39178","aliases":["EUVD-2021-2024","GHSA-9gr3-7897-pp7m"],"status":"published","title":"XSS in Image Optimization API for Next.js versions between 10.0.0 and 11.1.0","description":"Next.js is a React framework. Versions of Next.js between 10.0.0 and 11.0.0 contain a cross-site scripting vulnerability. In order for an instance to be affected by the vulnerability, the `next.config.js` file must have `images.domains` array assigned and the image host assigned in `images.domains` must allow user-provided SVG. If the `next.config.js` file has `images.loader` assigned to something other than default or the instance is deployed on Vercel, the instance is not affected by the vulnerability. The vulnerability is patched in Next.js version 11.1.1.","severity":{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.01139,"percentile":0.66867,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-79"],"published":"2021-08-30T23:55:09Z","modified":"2026-10-20T10:54:53Z","fixes":[{"ecosystem":"npm","package":"next","fixed_in":["11.1.1"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"next","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"10.0.0"},{"fixed":"11.1.1"}]}]},{"source":"osv","ecosystem":"npm","package":"next","ranges":[{"type":"SEMVER","events":[{"introduced":"10.0.0"},{"fixed":"11.1.1"}]}]}],"products":[{"vendor":"vercel","product":"next.js"}],"references":[{"url":"https://github.com/vercel/next.js/security/advisories/GHSA-9gr3-7897-pp7m","tags":["x_refsource_CONFIRM","x_transferred","Patch","Third Party Advisory","fix","web"]},{"url":"https://github.com/vercel/next.js/releases/tag/v11.1.1","tags":["x_refsource_MISC","x_transferred","Patch","Release Notes","Third Party Advisory","fix","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-39178","tags":["advisory"]},{"url":"https://github.com/vercel/next.js/pull/28620","tags":["web"]},{"url":"https://github.com/vercel/next.js/commit/7afc97c5744b38bdf36aa7f87625f438224688aa","tags":["web"]},{"url":"https://github.com/advisories/GHSA-9gr3-7897-pp7m"},{"url":"https://github.com/vercel/next.js","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2021-39178","title":"XSS in Image Optimization API for Next.js versions between 10.0.0 and 11.1.0","description":"Next.js is a React framework. Versions of Next.js between 10.0.0 and 11.0.0 contain a cross-site scripting vulnerability. In order for an instance to be affected by the vulnerability, the `next.config.js` file must have `images.domains` array assigned and the image host assigned in `images.domains` must allow user-provided SVG. If the `next.config.js` file has `images.loader` assigned to something other than default or the instance is deployed on Vercel, the instance is not affected by the vulnerability. The vulnerability is patched in Next.js version 11.1.1.","status":"published","published":"2021-08-30T23:55:09Z","modified":"2024-08-04T01:58:18.141Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:33:09.864034Z"}],"euvd":[{"id":"EUVD-2021-2024","description":"Next.js is a React framework. Versions of Next.js between 10.0.0 and 11.0.0 contain a cross-site scripting vulnerability. In order for an instance to be affected by the vulnerability, the `next.config.js` file must have `images.domains` array assigned and the image host assigned in `images.domains` must allow user-provided SVG. If the `next.config.js` file has `images.loader` assigned to something other than default or the instance is deployed on Vercel, the instance is not affected by the vulnerability. The vulnerability is patched in Next.js version 11.1.1.","status":"published","published":"2021-08-30T23:55:09Z","modified":"2024-08-04T01:58:18Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H","level":"high"}],"updated_at":"2026-11-03T03:24:24.305495Z"}],"ghsa":[{"id":"GHSA-9gr3-7897-pp7m","title":"XSS in Image Optimization API for Next.js","description":"### Impact\n- **Affected:** All of the following must be true to be affected\n    - Next.js between version 10.0.0 and 11.1.0\n    - The `next.config.js` file has [`images.domains`](https://nextjs.org/docs/basic-features/image-optimization#domains) array assigned\n    - The image host assigned in [`images.domains`](https://nextjs.org/docs/basic-features/image-optimization#domains) allows user-provided SVG\n- **Not affected**: The `next.config.js` file has [`images.loader`](https://nextjs.org/docs/basic-features/image-optimization#loader) assigned to something other than default\n- **Not affected**: Deployments on [Vercel](https://vercel.com) are not affected\n\n### Patches\n[Next.js v11.1.1](https://github.com/vercel/next.js/releases/tag/v11.1.1)\n\n","status":"published","published":"2021-09-01T18:24:22Z","modified":"2023-03-31T15:47:01Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:36:49.768564Z"}],"nvd":[{"id":"CVE-2021-39178","description":"Next.js is a React framework. Versions of Next.js between 10.0.0 and 11.0.0 contain a cross-site scripting vulnerability. In order for an instance to be affected by the vulnerability, the `next.config.js` file must have `images.domains` array assigned and the image host assigned in `images.domains` must allow user-provided SVG. If the `next.config.js` file has `images.loader` assigned to something other than default or the instance is deployed on Vercel, the instance is not affected by the vulnerability. The vulnerability is patched in Next.js version 11.1.1.","status":"published","published":"2021-08-31T00:15:07.203Z","modified":"2026-06-17T04:03:15.377Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H","level":"high","assessor":"secondary"},{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"primary"},{"version":"2.0","score":4.3,"vector":"AV:N/AC:M/Au:N/C:N/I:P/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:06:57.67549Z"}],"osv":[{"id":"CVE-2021-39178","description":"Next.js is a React framework. Versions of Next.js between 10.0.0 and 11.0.0 contain a cross-site scripting vulnerability. In order for an instance to be affected by the vulnerability, the `next.config.js` file must have `images.domains` array assigned and the image host assigned in `images.domains` must allow user-provided SVG. If the `next.config.js` file has `images.loader` assigned to something other than default or the instance is deployed on Vercel, the instance is not affected by the vulnerability. The vulnerability is patched in Next.js version 11.1.1.","status":"published","published":"2021-08-31T00:15:07.203Z","modified":"2026-10-20T10:54:53.096950995Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T15:44:20.843843Z"},{"id":"GHSA-9gr3-7897-pp7m","title":"XSS in Image Optimization API for Next.js","description":"### Impact\n- **Affected:** All of the following must be true to be affected\n    - Next.js between version 10.0.0 and 11.1.0\n    - The `next.config.js` file has [`images.domains`](https://nextjs.org/docs/basic-features/image-optimization#domains) array assigned\n    - The image host assigned in [`images.domains`](https://nextjs.org/docs/basic-features/image-optimization#domains) allows user-provided SVG\n- **Not affected**: The `next.config.js` file has [`images.loader`](https://nextjs.org/docs/basic-features/image-optimization#loader) assigned to something other than default\n- **Not affected**: Deployments on [Vercel](https://vercel.com) are not affected\n\n### Patches\n[Next.js v11.1.1](https://github.com/vercel/next.js/releases/tag/v11.1.1)\n\n","status":"published","published":"2021-09-01T18:24:22Z","modified":"2026-07-08T06:27:32.57546373Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:46:43.875515Z"}]}}