CVE-2026-22036: Undici Remote Code Execution Vulnerability

MODERATE
Advisory Identifier: GHSA-g9mf-h72j-4rw9
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CVSS 5.9
CWE-770
Published
Advisory Summary

CVE-2026-22036 is a MODERATE (CVSS 5.9) remote code execution vulnerability (CWE-770: Allocation of Resources Without Limits or Throttling) affecting Undici libraries in the npm ecosystem. The issue involves undici has an unbounded decompression chain in http responses on node.js fetch api via content-encoding leads to resource exhaustion. Remediation is available by upgrading affected packages to version 7.18.2, 6.23.0.

CVE-2026-22036 at a Glance

CVE Identifier CVE-2026-22036
GHSA Identifier GHSA-g9mf-h72j-4rw9
Severity MODERATE
CVSS v3.1 Base Score 5.9
CWE Classification CWE-770: Allocation of Resources Without Limits or Throttling
Affected Product Undici
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-2026-22036

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

undici fixed: 7.18.2 
npm install undici@7.18.2
undici fixed: 6.23.0 
npm install undici@6.23.0
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 undici

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-22036, inspect your project dependencies using npm:

npm ls undici

Analyze the terminal output to locate any version of Undici in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 7.18.2), your application is affected.

Note: The npm ls undici 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 Undici, 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 The `fetch()` API supports chained HTTP encoding algorithms for response content according to RFC 9110 (e.g., Content-Encoding: gzip, br). This is also supported by the undici decompress interceptor. However, the number of links in the decompression chain is unbounded and the default maxHeaderSize allows a malicious server to insert thousands compression steps leading to high CPU usage and excessive memory allocation. ### Patches Upgrade to 7.18.2 or 6.23.0. ### Workarounds It is possible to apply an undici interceptor and filter long `Content-Encoding` sequences manually. ### References * https://hackerone.com/reports/3456148 * https://github.com/advisories/GHSA-gm62-xv2j-4w53 * https://curl.se/docs/CVE-2022-32206.html

CVE-2026-22036 Affected Undici Versions

2 component(s)
Fixed Versions:
7.18.26.23.0
Product / Package Ecosystem Affected Versions Fixed Version
undici
npm/undici
npm
≥ 7.0.0
< 7.18.2
7.18.2
undici
npm/undici
npm
< 6.23.0
6.23.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/nodejs/undici/security/advisories/GHSA-g9mf-h72j-4rw9
NVD — CVE-2026-22036 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-22036
Security Fix Commit FIX COMMIT
https://github.com/nodejs/undici/commit/b04e3cbb569c1596f86c108e9b52c79d8475dcb3
Undici Source Repository REPOSITORY
https://github.com/nodejs/undici

Frequently Asked Questions

What is CVE-2026-22036?
CVE-2026-22036 is a security vulnerability in Undici involving Undici has an unbounded decompression chain in HTTP responses on Node.js Fetch API via Content-Encoding leads to resource exhaustion under CWE-770: Allocation of Resources Without Limits or Throttling.
Which Undici versions are affected?
Affected versions include releases prior to 7.18.2, 6.23.0 across affected packages: undici.
What version fixes CVE-2026-22036?
Upgrading to 7.18.2, 6.23.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is undici affected?
Yes, undici is affected in releases prior to 7.18.2, 6.23.0. Upgrade your dependency to 7.18.2, 6.23.0 or later.
What is the CVSS score of CVE-2026-22036?
CVE-2026-22036 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-2026-22036?
CVE-2026-22036 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-2026-22036?
Run the dependency tree command: 'npm ls undici'. 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-g9mf-h72j-4rw9",
  "modified" : "2026-01-22T20:17:07Z",
  "published" : "2026-01-14T21:06:08Z",
  "aliases" : [ "CVE-2026-22036" ],
  "summary" : "Undici has an unbounded decompression chain in HTTP responses on Node.js Fetch API via Content-Encoding leads to resource exhaustion",
  "details" : "### Impact\n\nThe `fetch()` API supports chained HTTP encoding algorithms for response content according to RFC 9110 (e.g., Content-Encoding: gzip, br). This is also supported by the undici decompress interceptor.\n\nHowever, the number of links in the decompression chain is unbounded and the default maxHeaderSize allows a malicious server to insert thousands compression steps leading to high CPU usage and excessive memory allocation.\n\n### Patches\n\nUpgrade to 7.18.2 or 6.23.0.\n\n### Workarounds\n\nIt is possible to apply an undici interceptor and filter long `Content-Encoding` sequences manually.\n\n### References\n\n* https://hackerone.com/reports/3456148\n* https://github.com/advisories/GHSA-gm62-xv2j-4w53\n* https://curl.se/docs/CVE-2022-32206.html",
  "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" : "undici"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "7.0.0"
      }, {
        "fixed" : "7.18.2"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "undici"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "6.23.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/nodejs/undici/security/advisories/GHSA-g9mf-h72j-4rw9"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-22036"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nodejs/undici/commit/b04e3cbb569c1596f86c108e9b52c79d8475dcb3"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/nodejs/undici"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-770" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-01-14T21:06:08Z",
    "nvd_published_at" : "2026-01-14T19:16:47Z"
  }
}