CVE-2026-64647

mediumpriority · track · 22EPSS 0.003 · 24 %ileDEEUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
0.32% (24th) EPSS
CVSS 5.4 · medium
Is it mine?
10 products
Check your exposure
Who says so?
4 sources
enisa_euvd · cert_bund · nvd · osv

EPSS · scored 2026-10-27

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 bodies with a content type charset other than UTF-8. For example, the UTF-16 byte sequences for 삃삃 and 섄섄 in the request body would share the same cache. This issue has been fixed in versions 15.5.21 and 16.2.11.

01

cvss

Technical severity, 0–10. One row per scoring source.

6.3
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 1.7–6.3

v3.15.4mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:Nprimary · NVD / NIST USexploitability 2.8 · impact 2.5
v4.06.3mediumCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:Nsecondary · ENISA EU
v4.06.3mediumCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/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:Xsecondary · security-advisories@github.com
v4.01.7lowCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/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:Xsecondary · CVSS-BT (t0sche)
02

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-116USCWE-116US
04

affected products (10)

Products and version ranges known to be affected.

05

advisories (2)

Vendor and ecosystem advisories describing this.

  • WID-SEC-W-2026-2468Vercel Next.js: Mehrere SchwachstellenDeutsch2026-07-21csaf · cert_bundDE

    Ein Angreifer kann mehrere Schwachstellen in Vercel Next.js ausnutzen, um Daten zu manipulieren, um Informationen offenzulegen, um einen Denial of Service Angriff durchzuführen, und um Sicherheitsvorkehrungen zu umgehen.

  • GHSA-4633-3j49-mh5qNext.js: Cache confusion of response bodies for requests with bodies containing invalid UTF-8 byte sequences2026-07-22ghsa · osvUS

    ## Impact 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 bodies with a content type charset other than UTF-8. For example, the UTF-16 byte sequences for `삃삃` and `섄섄` in the request body would share the same cache. ## Workarounds If you cannot upgrade, consider only making fetch requests with UTF-8 bodies (default in Next.js). Applications using Pages Router are not vulnerable.

06

also known as (2)

Other names and identifiers for this entity.

07

sources

Which sources assert this record, and when.

enisa_euvdcert_bundnvdosvNVDCVE.orgMITRE
published 2026-07-27modified 2026-10-24
08

references (10)

External citations — patches, advisories, analysis.

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