Confidential response disclosure via mismatched fetch cache keys
Published Jul 27, 2026 · Updated Jul 27, 2026
Cache confusion in Next.js 13.0.0 through 15.5.20 and 16.0.0 through 16.2.10 allows remote attackers to read cached POST responses. The patched fetch wrapper keyed cacheability and response storage from a base Request while native fetch applied conflicting init overrides to the effective request. Exposure requires an App Router server-side fetch call that passes a Request and a different init; Pages Router applications are unaffected.
Summary
What happened
Cache confusion in Next.js 13.0.0 through 15.5.20 and 16.0.0 through 16.2.10 allows remote attackers to read cached POST responses. The patched fetch wrapper keyed cacheability and response storage from a base Request while native fetch applied conflicting init overrides to the effective request. Exposure requires an App Router server-side fetch call that passes a Request and a different init; Pages Router applications are unaffected.
The record
- CVE
- CVE-2026-64648
- Published
- Jul 27, 2026
- Updated
- Jul 27, 2026
- Vendor
- Vercel
- Product
- Next.js
- Classifications
- CWE-524, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 27, 2026CVE publishedPublication date reported by the CVE source.
- Jul 27, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 13.0.0, < 15.5.21
- Affected versionversion=>= 16.0.0, < 16.2.11
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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