CVE-2026-44582: Next Next.js Vulnerable To Cache Poisoning Vulnerability

LOW
Advisory Identifier: GHSA-vfv6-92ff-j949
Share
CVSS 3.7
CWE-328
Published
Advisory Summary

CVE-2026-44582 is a LOW (CVSS 3.7) next.js vulnerable to cache poisoning vulnerability (CWE-328: Use of Weak Hash) affecting Next libraries in the npm ecosystem. The issue involves next.js vulnerable to cache poisoning via collisions in react server component cache-busting. Remediation is available by upgrading affected packages to version 15.5.16, 16.2.5.

CVE-2026-44582 at a Glance

CVE Identifier CVE-2026-44582
GHSA Identifier GHSA-vfv6-92ff-j949
Severity LOW
CVSS v3.1 Base Score 3.7
CWE Classification CWE-328: Use of Weak Hash
Affected Product Next
Package Ecosystem npm
Published Date
Last Updated

Security Impact

CVSS: 3.7

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:L/A:N).

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 Low (I:L)
Availability None (A:N)

How to Fix CVE-2026-44582

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-2026-44582, 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-328: Use of Weak Hash, where the product uses an algorithm that produces a digest (output value) that does not meet security expectations for a hash function that allows an adversary to reasonably determine the original input (preimage attack), find another input that can produce the same hash (2nd preimage attack), or find multiple inputs that evaluate to the same hash (birthday attack). 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 React Server Component responses can be vulnerable to cache poisoning in deployments that rely on shared caches with insufficient response partitioning. In affected conditions, collisions in the `_rsc` cache-busting value can allow an attacker to poison cache entries so users receive the wrong response variant for a given URL. ### Fix We strengthened the `_rsc` cache-busting mechanism to make practical collisions significantly harder and to better separate response variants that should not share cache entries. ### Workarounds If you cannot upgrade immediately, ensure intermediary caches correctly honor `Vary` for RSC-related request headers, or disable shared caching for affected RSC responses until you can deploy a patched release.

CVE-2026-44582 Affected Next Versions

2 component(s)
Fixed Versions:
15.5.1616.2.5
Product / Package Ecosystem Affected Versions Fixed Version
next
npm/next
npm
≥ 13.4.6
< 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-vfv6-92ff-j949
NVD — CVE-2026-44582 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-44582
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-2026-44582?
CVE-2026-44582 is a security vulnerability in Next involving Next.js vulnerable to cache poisoning via collisions in React Server Component cache-busting under CWE-328: Use of Weak Hash.
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-2026-44582?
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-2026-44582?
CVE-2026-44582 has a CVSS v3.1 base score of 3.7 (LOW) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N.
What CWE is associated with CVE-2026-44582?
CVE-2026-44582 is classified under CWE-328: Use of Weak Hash (The product uses an algorithm that produces a digest (output value) that does not meet security expectations for a hash function that allows an adversary to reasonably determine the original input (preimage attack), find another input that can produce the same hash (2nd preimage attack), or find multiple inputs that evaluate to the same hash (birthday attack).).
How can I check npm dependencies for CVE-2026-44582?
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-vfv6-92ff-j949",
  "modified" : "2026-05-14T20:38:32Z",
  "published" : "2026-05-11T15:56:48Z",
  "aliases" : [ "CVE-2026-44582" ],
  "summary" : "Next.js vulnerable to cache poisoning via collisions in React Server Component cache-busting",
  "details" : "### Impact\n\nReact Server Component responses can be vulnerable to cache poisoning in deployments that rely on shared caches with insufficient response partitioning. In affected conditions, collisions in the `_rsc` cache-busting value can allow an attacker to poison cache entries so users receive the wrong response variant for a given URL.\n\n### Fix\n\nWe strengthened the `_rsc` cache-busting mechanism to make practical collisions significantly harder and to better separate response variants that should not share cache entries.\n\n### Workarounds\n\nIf you cannot upgrade immediately, ensure intermediary caches correctly honor `Vary` for RSC-related request headers, or disable shared caching for affected RSC responses until you can deploy a patched release.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "next"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "13.4.6"
      }, {
        "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-vfv6-92ff-j949"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-44582"
  }, {
    "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-328" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-11T15:56:48Z",
    "nvd_published_at" : "2026-05-13T18:16:19Z"
  }
}