CVE-2026-64647: Next.js is a React framework for building full-stack web applications

Q: How do I fix CVE-2026-64647?

next.js: upgrade to 15.5.21, 16.2.11. Exact commands for each OS are on this page.

Q: Is CVE-2026-64647 being exploited?

CVE-2026-64647 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-64647 affect?

CVE-2026-64647 affects next.js. Severity is medium (CVSS 5.4). Next.js is a React framework for building full-stack web applications. In versions 12.0.0 through 15.5.20 and 16.0.0 through 16.2.10, a server-side fetch with a request body may return a cached response body from a different request to the

Q: How urgent is CVE-2026-64647?

Priority 25/100. No elevated risk signals yet.

Routine

MEDIUM 5.4UPGRADE

CVE-2026-64647 is a medium-severity flaw (CVSS 5.4) affecting next.js. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Next.js is a React framework for building full-stack web applications. In versions 12.0.0 through 15.5.20 and 16.0.0 through 16.2.10, a server-side fetch with a request body may return a cached response body from a different request to the same URL but different body. Confidential data in the POST's response body would then leak to unauthorized requests. Though the request itself will not be deduped. This is only an issue when receiving request b

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.3% (top 77%)
CISA exploited list	No
Weakness	CWE-116
Published	2026-07-27
Last modified	2026-10-24

Publisher (CNA): GitHub, Inc. · Vendor: vercel

Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-27 19:17 UTCPublished CVE record published
2026-10-24 13:10 UTCUpdated Record last modified

vercel next.js UPGRADE

Affected: >= 13.0.0 and < 15.5.21 · >= 16.0.0 and < 16.2.11

Fixed in: 15.5.21, 16.2.11

Safe to downgrade to: a release before 13.0.0

1. Check installed version

npm ls next.js

2. UPGRADE to 15.5.21

npm install next.js@">=15.5.21"

3. If no update is available yet, DOWNGRADE to a release before 13.0.0

npm view next.js versions npm install next.js@"<13.0.0"

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-64647?

next.js: upgrade to 15.5.21, 16.2.11. Exact commands for each OS are on this page.

Is CVE-2026-64647 being exploited?

CVE-2026-64647 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-64647 affect?

CVE-2026-64647 affects next.js. Severity is medium (CVSS 5.4). Next.js is a React framework for building full-stack web applications. In versions 12.0.0 through 15.5.20 and 16.0.0 through 16.2.10, a server-side fetch with a request body may return a cached response body from a different request to the

How urgent is CVE-2026-64647?

Priority 25/100. No elevated risk signals yet.

Software pages

React vulnerabilities · Next.js vulnerabilities

Related CVEs

CVE-2026-64641 HIGH 7.5 UPGRADE Next.js is a React framework for building full-stack web applications
CVE-2026-64642 HIGH 8.2 UPGRADE Next.js is a React framework for building full-stack web applications
CVE-2026-64649 MEDIUM 6.5 UPGRADE Next.js is a React framework for building full-stack web applications
CVE-2026-64644 MEDIUM 5.3 UPGRADE Next.js is a React framework for building full-stack web applications
CVE-2026-64643 MEDIUM 5.3 UPGRADE Next.js is a React framework for building full-stack web applications

References

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