---
id: CVE-2026-9679
title: >-
  undici: undici vulnerable to HTTP header injection via Set-Cookie
  percent-decoding (CVE-2026-9679)
summary: >-
  A flaw was found in undici. The cookie parser in the `parseSetCookie` function
  incorrectly decodes cookie values, which is contrary to standard
  specifications. This vulnerability allows an attacker-controlled upstream to
  inject arbitrary H…
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'
cvssSource: vendor
cwe: CWE-93
vendor: Red Hat
product: Red Hat Openshift Data Foundation 4.18
affected:
  - cryostat 4
  - openshift_pipelines
  - amq_broker 7
  - build_of_podman_desktop
  - developer_hub
  - enterprise_linux 10
  - enterprise_linux 8
  - enterprise_linux 9
  - hardened_images
  - openshift_ai_rhoai
  - openshift_container_platform 4
  - openshift_dev_spaces
  - self_service_automation_portal 2
  - openshift_data_foundation 4.18
patched:
  - hardened_images
  - openshift_data_foundation 4.18
published: '2026-06-17'
updated: '2026-10-01'
sourceUpdated: '2026-10-01T17:19:44+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-9679.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-9679.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-9679'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2490022'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-9679'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-9679'
  - url: 'https://cna.openjsf.org/security-advisories.html'
  - url: 'https://github.com/nodejs/undici/security/advisories/GHSA-p88m-4jfj-68fv'
  - url: 'https://access.redhat.com/errata/RHSA-2026:38236'
  - url: 'https://access.redhat.com/errata/RHSA-2026:38009'
  - url: 'https://access.redhat.com/errata/RHSA-2026:56431'
  - url: 'https://github.com/advisories/GHSA-p88m-4jfj-68fv'
tags:
  - csaf
  - vex
  - red-hat
  - ghsa
  - npm
epss: 0.00257
epssPercentile: 0.17289
ecosystem: npm
ingestedAt: '2026-06-22T15:59:08.196Z'
---

## Overview

A flaw was found in undici. The cookie parser in the `parseSetCookie` function incorrectly decodes cookie values, which is contrary to standard specifications. This vulnerability allows an attacker-controlled upstream to inject arbitrary HTTP response headers, such as `Set-Cookie`, `Location`, or `Cache-Control`. The primary consequence is HTTP response header injection, which can lead to session fixation, open redirect, or cache poisoning.

## Vendor advisories

- **RHSA-2026:38236** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-07-11 · [advisory](https://access.redhat.com/errata/RHSA-2026:38236)
- **RHSA-2026:38009** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-07-10 · [advisory](https://access.redhat.com/errata/RHSA-2026:38009)
- **RHSA-2026:56431** · Red Hat · fixed in: Red Hat Openshift Data Foundation 4.18 · released 2026-08-18 · [advisory](https://access.redhat.com/errata/RHSA-2026:56431)
- **Red Hat VEX** · Moderate · affected: Cryostat 4, OpenShift Pipelines, Red Hat AMQ Broker 7, Red Hat Build of Podman Desktop, Red Hat Developer Hub, Red Hat Enterprise Linux 10, … · no fix planned: Red Hat Hardened Images, Cryostat 4, OpenShift Pipelines, Red Hat AMQ Broker 7, … · updated 2026-10-01 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-9679.json)

**undici: undici vulnerable to HTTP header injection via Set-Cookie percent-decoding** — rated Moderate by Red Hat. Released 2026-06-17, updated 2026-10-01.

Affected:

- Cryostat 4
- OpenShift Pipelines
- Red Hat AMQ Broker 7
- Red Hat Build of Podman Desktop
- Red Hat Developer Hub
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat Hardened Images
- Red Hat OpenShift AI (RHOAI)
- Red Hat OpenShift Container Platform 4
- Red Hat OpenShift Dev Spaces
- Self-service automation portal 2

Fixed:

- Red Hat Hardened Images
- Red Hat Openshift Data Foundation 4.18

No fix planned:

- Red Hat Hardened Images
- Cryostat 4
- OpenShift Pipelines
- Red Hat AMQ Broker 7
- Red Hat Build of Podman Desktop
- Red Hat Developer Hub
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift AI (RHOAI)
- Red Hat OpenShift Container Platform 4
- Red Hat OpenShift Dev Spaces
- Self-service automation portal 2

Not affected:

- Red Hat Openshift Data Foundation 4.18
- Red Hat Hardened Images

## Remediation

For details on how to apply this update, which includes the changes described in this advisory, refer to:
https://images.redhat.com/ https://access.redhat.com/errata/RHSA-2026:38236
For details on how to apply this update, which includes the changes described in this advisory, refer to:
https://images.redhat.com/ https://access.redhat.com/errata/RHSA-2026:38009
Before applying this update, make sure all previously released errata
relevant to your system have been applied.

For details on how to apply this update, refer to:

https://docs.redhat.com/en/documentation/red_hat_openshift_data_foundation/4.18/html/updating_openshift_data_foundation/updating-ocs-to-odf_rhodf https://access.redhat.com/errata/RHSA-2026:56431

Workarounds / mitigations:

- Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

## Package advisory (CVE-2026-9679)

Affected packages:

- `undici < 6.27.0`
- `undici >= 7.0.0, < 7.28.0`
- `undici >= 8.0.0, < 8.5.0`

Patched in:

- `undici 6.27.0`
- `undici 7.28.0`
- `undici 8.5.0`

Source: https://github.com/advisories/GHSA-p88m-4jfj-68fv