---
id: CVE-2026-109841
title: undici is an HTTP client library for Node.js
summary: >-
  undici is an HTTP client library for Node.js. In versions 7.15.0 through
  7.30.0 and 8.0.0 through 8.12.1, its fetch() implementation verifies
  Subresource Integrity metadata by matching the algorithm token against a
  lowercase-only set, ev…
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N'
cwe:
  - CWE-178
  - CWE-354
vendor: undici
product: undici
affected:
  - undici >= 7.15.0 < 7.30.1
  - undici >= 8.0.0 < 8.12.2
published: '2026-10-15'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T19:17:21.640'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-109841'
references:
  - url: 'https://cna.openjsf.org/security-advisories.html'
    label: ce714d77-add3-4f53-aff5-83d477b104bb
  - url: 'https://github.com/nodejs/undici/security/advisories/GHSA-f72v-6w45-q472'
    label: ce714d77-add3-4f53-aff5-83d477b104bb
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-109841.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-109841'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2553669'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-109841'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-109841'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
ingestedAt: '2026-10-15T19:25:46.400Z'
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-16T20:04:31.429219Z'
---

## Overview

undici is an HTTP client library for Node.js. In versions 7.15.0 through 7.30.0 and 8.0.0 through 8.12.1, its fetch() implementation verifies Subresource Integrity metadata by matching the algorithm token against a lowercase-only set, even though the SRI specification defines the token by its ASCII-lowercase form, so a valid but non-lowercase token such as an uppercase or mixed-case SHA256 is treated as unknown and skipped. When no recognized algorithm remains, undici treats the integrity list as empty and accepts the response, so a server returning a body that does not match the pinned digest passes the check. An attacker who controls only the response body can therefore deliver attacker-controlled bytes to an application that pinned a valid uppercase or mixed-case SRI token, with no integrity error, affecting response integrity only. The issue is fixed in undici 7.30.1 and 8.12.2, which normalize the algorithm token to ASCII lowercase before validation, and users should upgrade to one of those versions or later. As a workaround, use lowercase algorithm tokens such as sha256, sha384, or sha512 in integrity metadata.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Cryostat 4, Exploit Intelligence, Red Hat AMQ Broker 7, Red Hat Ansible Automation Platform 2, Red Hat Build of Podman Desktop, Red Hat Developer Hub, … · no fix planned: Exploit Intelligence, Secrets Management Console for Red Hat OpenShift, Red Hat Hardened Images, Cryostat 4, … · updated 2026-10-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-109841.json)