Security Bulletin
Summary
IBM Documentation Offline utilizes Node.js as a third-party component, which contains a vulnerability that could potentially affect your product's stability and security. CVE-2026-21710 (CVSS: 3.1) is a denial-of-service (DoS) vulnerability identified in the Node.js core HTTP module. An unauthenticated remote attacker can exploit this flaw to cause type errors and unhandled promise rejections potentially leading to monitoring blind spots and/or file descriptor leaks by sending a single, specially crafted HTTP request. Users of IBM Documentation Offline are encouraged to apply the necessary update to mitigate these risks.
Vulnerability Details
CVEID: CVE-2026-21710
DESCRIPTION: A flaw in Node.js HTTP request handling causes an uncaught `TypeError` when a request is received with a header named `__proto__` and the application accesses `req.headersDistinct`.
When this occurs, `dest["__proto__"]` resolves to `Object.prototype` rather than `undefined`, causing `.push()` to be called on a non-array. This exception is thrown synchronously inside a property getter and cannot be intercepted by `error` event listeners, meaning it cannot be handled without wrapping every `req.headersDistinct` access in a `try/catch`.
* This vulnerability affects all Node.js HTTP servers on **20.x, 22.x, 24.x, and v25.x**
CWE: CWE-770: Allocation of Resources Without Limits or Throttling
CVSS Source: CISA-ADP
CVSS Base score: 7.5
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
Affected Products and Versions
| Affected Product(s) | Version(s) |
| IBM Documentation Offline | 1.0.0 - 1.3.5 |
Remediation/Fixes
IBM strongly recommends addressing the vulnerability/vulnerabilities now by applying the following fix:
| Product(s) | Version(s) number and/or range | Remediation/Fix/Instructions |
| IBM Documetation Offline (electron version) | 1.0.0 - 1.3.5 | Download and install latest release (1.5.1) |
| IBM Documentation Offline (intranet version) | 1.0.0 - 1.3.5 | Update node.js you use to run the app to 24.14.1 |
Workarounds and Mitigations
Update to the latest version
Get Notified about Future Security Bulletins
References
Review this information as needed, no action required.
Acknowledgement
Change History
07 Sep 2026: Initial Publication
*The CVSS Environment Score is customer environment specific and will ultimately impact the Overall CVSS Score. Customers can evaluate the impact of this vulnerability in their environments by accessing the links in the Reference section of this Security Bulletin.
Disclaimer
According to the Forum of Incident Response and Security Teams (FIRST), the Common Vulnerability Scoring System (CVSS) is an "industry open standard designed to convey vulnerability severity and help to determine urgency and priority of response." IBM PROVIDES THE CVSS SCORES ""AS IS"" WITHOUT WARRANTY OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. CUSTOMERS ARE RESPONSIBLE FOR ASSESSING THE IMPACT OF ANY ACTUAL OR POTENTIAL SECURITY VULNERABILITY. In addition to other efforts to address potential vulnerabilities, IBM periodically updates the record of components contained in our product offerings. As part of that effort, if IBM identifies previously unidentified packages in a product/service inventory, we address relevant vulnerabilities regardless of CVE date. Inclusion of an older CVEID does not demonstrate that the referenced product has been used by IBM since that date, nor that IBM was aware of a vulnerability as of that date. We are making clients aware of relevant vulnerabilities as we become aware of them. "Affected Products and Versions" referenced in IBM Security Bulletins are intended to be only products and versions that are supported by IBM and have not passed their end-of-support or warranty date. Thus, failure to reference unsupported or extended-support products and versions in this Security Bulletin does not constitute a determination by IBM that they are unaffected by the vulnerability. Reference to one or more unsupported versions in this Security Bulletin shall not create an obligation for IBM to provide fixes for any unsupported or extended-support products or versions.
Document Location
Worldwide
Was this topic helpful?
Document Information
Modified date:
07 September 2026
Initial Publish date:
07 September 2026
UID
ibm17286506