CVE-2026-64649
What it is
Next.js is a React framework for building full-stack web applications. In versions 14.1.1 through 15.5.20 and 16.0.0 through 16.2.10, when a Server Action forwards or redirects a request, an attacker can cause the server to send that outbound request to a malicious host (Server-Side Request Forgery). This requires the attacker's request to control Host-associated headers. In some configurations, it's also possible to obtain internal values that weaken middleware/proxy authorization. Applications that use Server Actions are affected when the incoming host header is not fixed to a trusted value. This typically occurs on custom servers, or on deployments not behind a proxy that pins the host. Managed hosting pins the host upstream and is not affected; next start and standalone output do the same from version 14.2 onward. This issue has been fixed in versions 15.5.21 and 16.2.11.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of data exposure.
- Exploit odds
- 0.5% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.5% in the next 30 days (EPSS).
- Severity: 8.3 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.5% · EPSS, next 30 days
- Weakness
- CWE-918 · Server-side request forgery
- Record status
- Analyzed
Affected
- Vercel next.js < 15.5.21
- Vercel next.js < 16.2.11
Attack profile CVSS 4.0 · 8.3
- Attack vector
- Network
- Complexity
- Low
- Attack requirements
- Present
- Privileges needed
- None
- User interaction
- None
- Confidentiality
- High
- Integrity
- Low
- Availability
- None
Raw vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-64649.md and follow it. Check whether this project is affected by CVE-2026-64649. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://github.com/vercel/next.js/commit/b51206321854193208c0805ba42acc49287f942b
- https://github.com/vercel/next.js/commit/e3e5666ccead3a15162793d697af5e48b7cc0498
- https://github.com/vercel/next.js/releases/tag/v15.5.21
- https://github.com/vercel/next.js/releases/tag/v16.2.11
- https://github.com/vercel/next.js/security/advisories/GHSA-89xv-2m56-2m9x
References
- https://github.com/vercel/next.js/commit/b51206321854193208c0805ba42acc49287f942b
- https://github.com/vercel/next.js/commit/e3e5666ccead3a15162793d697af5e48b7cc0498
- https://github.com/vercel/next.js/releases/tag/v15.5.21
- https://github.com/vercel/next.js/releases/tag/v16.2.11
- https://github.com/vercel/next.js/security/advisories/GHSA-89xv-2m56-2m9x