Security Bulletin
Summary
IBM Documentation Offline uses Node.js as its runtime environment. Node.js is affected by two vulnerabilities related to TLS hostname handling. CVE-2026-48618 involves improper handling of Unicode dot separators during TLS certificate verification, which could allow an attacker performing a man-in-the-middle attack to bypass wildcard certificate depth checks. CVE-2026-48930 involves C-string truncation of hostnames containing embedded NUL characters in resolver bindings, which could allow silent authority rebinding. IBM Documentation Offline may connect to a fixed IBM-controlled HTTPS endpoint for update checks; no user-supplied data is passed to hostname resolution APIs. IBM has addressed these vulnerabilities by updating the minimum required Node.js version.
Vulnerability Details
CVEID: CVE-2026-48618
DESCRIPTION: A flaw in Node.js TLS hostname handling can cause Node.js unicode dot separator handling can lead to tls wildcard-depth authentication bypass due to resolver and verifier hostname normalization mismat.
This can lead to confidentiality impact or bypass of the intended security boundary under affected configurations.
This vulnerability affects all supported release lines: **Node.js 22**, **Node.js 24**, and **Node.js 26**.
CWE: CWE-176: Improper Handling of Unicode Encoding
CVSS Source: NVD
CVSS Base score: 6.5
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N)
CVEID: CVE-2026-48930
DESCRIPTION: A flaw in Node.js TLS hostname handling can cause Embedded-nul hostnames can lead to silent authority rebinding due to c-string truncation in resolver bindings.
This vulnerability affects all supported release lines: **Node.js 22**, **Node.js 24**, and **Node.js 26**.
CWE: CWE-284: Improper Access Control
CVSS Source: NVD
CVSS Base score: 9.8
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
Affected Products and Versions
| Affected Product(s) | Version(s) |
| IBM Documentation Offline | 1.0.0 - 1.5.1 |
Remediation/Fixes
IBM strongly recommends addressing the vulnerability now.
| Product(s) | Version(s) number and/or range | Remediation/Fix/Instructions |
| IBM Documentation Offline | 1.0.0 - 1.5.1 | Download and install latest release (1.5.2) |
Workarounds and Mitigations
Users on corporate networks with trusted DNS and no intercepting proxies face no practical exposure to CVE-2026-48618. No mitigation is available for CVE-2026-48930 other than upgrading.
Get Notified about Future Security Bulletins
References
Acknowledgement
Change History
29 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:
29 September 2026
Initial Publish date:
29 September 2026
UID
ibm17290005