Undici: Use of Web Browser Cache Containing Sensitive Information (CVE-2026-13697)

What is affected, what to do

A flaw was found in undici. This vulnerability allows for cross-user information disclosure when malformed Cache-Control private directives cause private response bodies and headers, such as Set-Cookie data, to be stored in a shared cache and subsequently exposed to other users.

Update Undici to version 7.29.0, Undici to version 8.9.0.

Affected

• Undici lt 7.0.0..7.29.0
• Undici lt 8.0.0..8.9.0

Fixed in

• Undici 7.29.0
• Undici 8.9.0

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Metrics

Detection rules

No NEOSEC detection rule is available for this vulnerability yet.

Classification under NIS2 and CRA

Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

NIS2

NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

Read in glossary

High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.

CRA

The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

Read in glossary

From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.

ISO/IEC 27001

ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

Read in glossary

Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

Description

A flaw was found in undici. This vulnerability allows for cross-user information disclosure when malformed Cache-Control private directives cause private response bodies and headers, such as Set-Cookie data, to be stored in a shared cache and subsequently exposed to other users. Additionally, a specially crafted Cache-Control header can trigger an unhandled error in the cache parser, leading to a process termination and a Denial of Service (DoS). Both issues affect applications using the cache interceptor in shared mode.

Source: redhat_csaf, BSI CSAF, BSI WID Portal, cvelistv5, OSV (Open Source Vulnerabilities), NVD (NIST)

Vendors and products

• IBM App Connect Enterprise
• NodeJS Nodejs undici
• Undici Undici

Weakness classes (CWE)

• CWE-200Exposure of Sensitive Information to an Unauthorized Actor

  Class

  The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.

  Entry at MITRE CWE-200

• CWE-248Uncaught Exception

  Base

  An exception is thrown from a function, but it is not caught.

  Entry at MITRE CWE-248

• CWE-525Use of Web Browser Cache Containing Sensitive Information

  Variant

  The web application does not use an appropriate caching policy that specifies the extent to which each web page and associated form fields should be cached.

  Entry at MITRE CWE-525

References & sources

• github.comnodejs/undici/security/advisories/GHSA-4cwx-7wf7-3272web
• NVD (NIST)vuln/detail/CVE-2026-13697advisory
• github.comnodejs/undici/commit/4fe5bc5fefe5ac81a200fc8e1cf84b8bf8464451web
• cna.openjsf.orgsecurity-advisories.htmlweb
• github.comnodejs/undicipackage
• github.comnodejs/undici/releases/tag/v7.29.0web
• github.comnodejs/undici/releases/tag/v8.9.0web

Changes to this CVE

Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

1. 29.07.2026Record modifiedCISA ADP

   CISA assessment (SSVC): exploitation: none known, automatable: no

   Show the original change

   Individual changes of this event as published by NVD

   Type	Action	Before	After
   SSVC assessment	added	—	{"id":"CVE-2026-13697","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-07-29T17:53:46.323187Z"}

   Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

2. 29.07.2026ReceivedOpenJS Foundation

   CVSS V3.1: AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H

   Weakness type: CWE-200, CWE-248, CWE-525

   Description added or changed

   New references:

   • https://cna.openjsf.org/security-advisories.html
   • https://github.com/nodejs/undici/security/advisories/GHSA-4cwx-7wf7-3272
   Show 8 original changes

   Individual changes of this event as published by NVD

   Type	Action	Before	After
   Affected versions (publisher)	added	—	undici
   Description	added	—	undici's cache interceptor mishandles malformed Cache-Control private directives. In undici 7.0.0 up to before 7.29.0 and 8.0.0 up to before 8.9.0, a response carrying a degenerate qualified private directive, such as private set to an empty value, can be stored in the default shared cache and later served to a different caller with the same cache key, disclosing private response bodies and headers including Set-Cookie. Separately, a Cache-Control header that combines an unqualified private directive with a qualified one triggers an uncaught TypeError in the cache-control parser, which rejects the request and, depending on the consumer's error handling, can terminate the process. Both issues affect applications using the cache interceptor in shared mode, including the default configuration. The issues are fixed in undici 7.29.0 and 8.9.0.
   CVSS	added	—	AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H
   Weakness type (CWE)	added	—	CWE-200
   Weakness type (CWE)	added	—	CWE-248
   Weakness type (CWE)	added	—	CWE-525
   Reference	added	—	https://cna.openjsf.org/security-advisories.html
   Reference	added	—	https://github.com/nodejs/undici/security/advisories/GHSA-4cwx-7wf7-3272

   Source identifier: ce714d77-add3-4f53-aff5-83d477b104bb