CVE-2026-44579Network attack vector

Unauthenticated service interruption via external resume header

Published May 13, 2026 · Updated May 13, 2026

Resource exhaustion in Vercel Next.js 15.0.0 through 15.5.15 and 16.0.0 through 16.2.4 allows remote attackers to interrupt service. The server accepts an external Next-Resume header intended only for internal Partial Prerendering resume requests, causing request-body handling to deadlock and hold connections open. Only applications using Partial Prerendering through Cache Components are exposed; crafted POST requests to a Server Action consume file descriptors and server capacity until legitimate requests fail.

CVSS severity7.5
High
EPSS probability0.75%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in Vercel Next.js 15.0.0 through 15.5.15 and 16.0.0 through 16.2.4 allows remote attackers to interrupt service. The server accepts an external Next-Resume header intended only for internal Partial Prerendering resume requests, causing request-body handling to deadlock and hold connections open. Only applications using Partial Prerendering through Cache Components are exposed; crafted POST requests to a Server Action consume file descriptors and server capacity until legitimate requests fail.

The record

CVE
CVE-2026-44579
Published
May 13, 2026
Updated
May 13, 2026
Vendor
Vercel
Product
Next.js
Classifications
CWE-770, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 13, 2026CVE publishedPublication date reported by the CVE source.
  2. May 13, 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=>= 15.0.0, < 15.5.16
  2. Affected versionversion=>= 16.0.0, < 16.2.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Vercel · Next.jsversion=>= 15.0.0, < 15.5.16; version=>= 16.0.0, < 16.2.5

Published CVSS scores

7.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.003Application Exhaustion Flood

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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