CVE-2021-39178 json
XSS in Image Optimization API for Next.js versions between 10.0.0 and 11.1.0
published 5y ago modified 4mo ago also EUVD-2021-2024 , GHSA-9gr3-7897-pp7m
- cvss
- 7.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.1%
- EPSS 1.1% chance of exploitation in 30 days, percentile 66%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- npm next 11.1.1
- vercel next.js 11.1.1
Is CVE-2021-39178 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerExploit prediction
1.14% chance of exploitation in the next 30 days, higher than 66% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H |
| GitHub | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H |
| NVD | 3.1 | 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
| NVD | 2.0 | 4.3 | AV:N/AC:M/Au:N/C:N/I:P/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | next | >=10.0.0, <11.1.1 |
11.1.1 |
Affected products
- vercel next.js
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
- Technology feeds
References
-
github.com
/vercel/next.js/security/advisories/GHSA-9gr3-7897-pp7m
web, patch, third-party-advisory, advisory
-
github.com
/vercel/next.js/releases/tag/v11.1.1
web, patch, release-notes, third-party-advisory
-
github.com
/vercel/next.js/pull/28620
web
-
github.com
/vercel/next.js/commit/7afc97c5744b38bdf36aa7f87625f438224688aa
web
-
nvd.nist.gov
/vuln/detail/CVE-2021-39178
advisory
-
github.com
/vercel/next.js
package
Sources
- CVE List CVE-2021-39178
- GitHub Advisory GHSA-9gr3-7897-pp7m
- NVD CVE-2021-39178
- Maintainer advisory GHSA-9gr3-7897-pp7m
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
The maintainers of vercel/next.js published their own advisory on GitHub. Reviewed sources take precedence over it.