CVE-2026-44577: Next Denial of Service Vulnerability

MODERATE
Advisory Identifier: GHSA-h64f-5h5j-jqjh
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CVSS 5.9
CWE-770
Published
Advisory Summary

CVE-2026-44577 is a MODERATE (CVSS 5.9) denial of service vulnerability (CWE-770: Allocation of Resources Without Limits or Throttling) affecting Next libraries in the npm ecosystem. The issue involves next.js has a denial of service in the image optimization api. Remediation is available by upgrading affected packages to version 15.5.16, 16.2.5.

CVE-2026-44577 at a Glance

CVE Identifier CVE-2026-44577
GHSA Identifier GHSA-h64f-5h5j-jqjh
Severity MODERATE
CVSS v3.1 Base Score 5.9
CWE Classification CWE-770: Allocation of Resources Without Limits or Throttling
Affected Product Next
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 5.9

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2026-44577

To remediate this vulnerability, upgrade all affected Next dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

next fixed: 15.5.16 
npm install next@15.5.16
next fixed: 16.2.5 
npm install next@16.2.5
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls next

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-44577, inspect your project dependencies using npm:

npm ls next

Analyze the terminal output to locate any version of Next in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 15.5.16), your application is affected.

Note: The npm ls next command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-770: Allocation of Resources Without Limits or Throttling, where the product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated. In Next, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact When self-hosting Next.js with the default image loader, the Image Optimization API fetches local images entirely into memory without enforcing a maximum size limit. An attacker could cause out-of-memory conditions by requesting large local assets from the `/_next/image` endpoint that match the `images.localPatterns` configuration (by default, all patterns are allowed). - If you are using `images.localPatterns`, only the patterns in that array are impacted. - If you are using `images.unoptimized: true`, you are NOT impacted. - If you are using `images.loader: 'custom'`, you are NOT impacted. - If you are using Vercel, you are NOT impacted. ### Fix We now apply response size limits consistently to internal image fetches, not just external ones, and fail oversized responses before they can exhaust process memory. This can be adjusted using the `images.maximumResponseBody` configuration. ### Workarounds If you cannot upgrade immediately, avoid routing large local assets through `/_next/image`, disable image optimization for large or untrusted local files, or block image optimization access to those assets at the edge. You can disable using the `images.localPatterns: []` configuration. This will still allow fetching remote images (which is not impacted).

CVE-2026-44577 Affected Next Versions

2 component(s)
Fixed Versions:
15.5.1616.2.5
Product / Package Ecosystem Affected Versions Fixed Version
next
npm/next
npm
≥ 10.0.0
< 15.5.16
15.5.16
next
npm/next
npm
≥ 16.0.0
< 16.2.5
16.2.5

References

GitHub Advisory / Wiki ADVISORY
https://github.com/vercel/next.js/security/advisories/GHSA-h64f-5h5j-jqjh
NVD — CVE-2026-44577 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-44577
Next Source Repository REPOSITORY
https://github.com/vercel/next.js
Next Release RELEASE
https://github.com/vercel/next.js/releases/tag/v15.5.16
Next Release RELEASE
https://github.com/vercel/next.js/releases/tag/v16.2.5

Frequently Asked Questions

What is CVE-2026-44577?
CVE-2026-44577 is a security vulnerability in Next involving Next.js has a Denial of Service in the Image Optimization API under CWE-770: Allocation of Resources Without Limits or Throttling.
Which Next versions are affected?
Affected versions include releases prior to 15.5.16, 16.2.5 across affected packages: next.
What version fixes CVE-2026-44577?
Upgrading to 15.5.16, 16.2.5 (or the latest patched release for your respective branch) resolves the vulnerability.
Is next affected?
Yes, next is affected in releases prior to 15.5.16, 16.2.5. Upgrade your dependency to 15.5.16, 16.2.5 or later.
What is the CVSS score of CVE-2026-44577?
CVE-2026-44577 has a CVSS v3.1 base score of 5.9 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2026-44577?
CVE-2026-44577 is classified under CWE-770: Allocation of Resources Without Limits or Throttling (The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.).
How can I check npm dependencies for CVE-2026-44577?
Run the dependency tree command: 'npm ls next'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-h64f-5h5j-jqjh",
  "modified" : "2026-05-14T20:38:16Z",
  "published" : "2026-05-11T15:56:05Z",
  "aliases" : [ "CVE-2026-44577" ],
  "summary" : "Next.js has a Denial of Service in the Image Optimization API",
  "details" : "### Impact\n\nWhen self-hosting Next.js with the default image loader, the Image Optimization API fetches local images entirely into memory without enforcing a maximum size limit. An attacker could cause out-of-memory conditions by requesting large local assets from the `/_next/image` endpoint that match the `images.localPatterns` configuration (by default, all patterns are allowed).\n\n- If you are using `images.localPatterns`, only the patterns in that array are impacted.\n- If you are using `images.unoptimized: true`, you are NOT impacted.\n- If you are using `images.loader: 'custom'`, you are NOT impacted.\n- If you are using Vercel, you are NOT impacted.\n\n### Fix\n\nWe now apply response size limits consistently to internal image fetches, not just external ones, and fail oversized responses before they can exhaust process memory.\n\nThis can be adjusted using the `images.maximumResponseBody` configuration.\n\n### Workarounds\n\nIf you cannot upgrade immediately, avoid routing large local assets through `/_next/image`, disable image optimization for large or untrusted local files, or block image optimization access to those assets at the edge.\n\nYou can disable using the `images.localPatterns: []` configuration. This will still allow fetching remote images (which is not impacted).",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "next"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "10.0.0"
      }, {
        "fixed" : "15.5.16"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "next"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "16.0.0"
      }, {
        "fixed" : "16.2.5"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/vercel/next.js/security/advisories/GHSA-h64f-5h5j-jqjh"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-44577"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/vercel/next.js"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vercel/next.js/releases/tag/v15.5.16"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/vercel/next.js/releases/tag/v16.2.5"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-770" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-11T15:56:05Z",
    "nvd_published_at" : "2026-05-13T17:16:23Z"
  }
}