CVE-2026-64645Network attack vector

SSRF and open redirect via unencoded hostname parameters

Published Jul 27, 2026 · Updated Jul 27, 2026

SSRF and open redirect flaws in Vercel Next.js allow remote attackers to send proxy requests or redirects to arbitrary hosts. The prepareDestination function compiled dynamic destination-hostname parameters without percent-encoding them, so crafted values changed the parsed host rather than remaining within the configured suffix. Exploitation requires a rewrites() or redirects() rule that places request-derived parameters in an external destination hostname; SSRF can expose internal responses, while redirects send clients to attacker-selected sites.

CVSS severity8.3
High
EPSS probability0.84%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF and open redirect flaws in Vercel Next.js allow remote attackers to send proxy requests or redirects to arbitrary hosts. The prepareDestination function compiled dynamic destination-hostname parameters without percent-encoding them, so crafted values changed the parsed host rather than remaining within the configured suffix. Exploitation requires a rewrites() or redirects() rule that places request-derived parameters in an external destination hostname; SSRF can expose internal responses, while redirects send clients to attacker-selected sites.

The record

CVE
CVE-2026-64645
Published
Jul 27, 2026
Updated
Jul 27, 2026
Vendor
Vercel
Product
Next.js
Classifications
CWE-601, CWE-918, T1090
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 27, 2026CVE publishedPublication date reported by the CVE source.
  2. 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.

  1. Affected versionversion=>= 12.0.0 < 15.5.21
  2. Affected versionversion=>= 16.0.0, < 16.2.11

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Vercel · Next.jsversion=>= 12.0.0 < 15.5.21; version=>= 16.0.0, < 16.2.11

Published CVSS scores

8.3GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:L/SI:L/SA:N
6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-601URL Redirection to Untrusted Site ('Open Redirect')
CWE-918Server-Side Request Forgery (SSRF)
T1090Proxy

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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