High severity · published Mar 18, 2026
CVE-2026-27979
Next.js: Unbounded postponed resume buffering can lead to DoS
7.5
CVSS
0.7%
EPSS
No
On KEV
Description
Next.js is a React framework for building full-stack web applications. Starting in version 16.0.1 and prior to version 16.1.7, a request containing the `next-resume: 1` header (corresponding with a PPR resume request) would buffer request bodies without consistently enforcing `maxPostponedStateSize` in certain setups. The previous mitigation protected minimal-mode deployments, but equivalent non-minimal deployments remained vulnerable to the same unbounded postponed resume-body buffering behavior. In applications using the App Router with Partial Prerendering capability enabled (via `experimental.ppr` or `cacheComponents`), an attacker could send oversized `next-resume` POST payloads that were buffered without consistent size enforcement in non-minimal deployments, causing excessive memory usage and potential denial of service. This is fixed in version 16.1.7 by enforcing size limits across all postponed-body buffering paths and erroring when limits are exceeded. If upgrading is not immediately possible, block requests containing the `next-resume` header, as this is never valid to be sent from an untrusted client.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.7% · higher than 53% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
NE
next.js · vercel
>= 16.0.1, < 16.1.7 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-27979
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-27979
Patch
https://github.com/vercel/next.js/commit/c885d4825f800dd1e49ead37274dcd08cdd6f3f1
Release Notes
https://github.com/vercel/next.js/releases/tag/v16.1.7
Mitigation
https://github.com/vercel/next.js/security/advisories/GHSA-h27x-g6w4-24gq
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