CVE-2026-21788
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedHCL Connections is vulnerable to a cross-site scripting attack where an attacker may leverage this issue to execute arbitrary script code in the browser of an unsuspecting user which leads to executing malicious script code. This may allow the attacker steal cookie-based authentication credentials and comprise user's account then launch other attacks.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceHCL Connections contains a stored cross-site scripting (XSS) vulnerability where unsanitized user input is reflected back in web pages, allowing attackers to inject malicious JavaScript that executes in the browsers of unsuspecting users.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data= 8.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Confirm HCL Connections versionCheck the installed HCL Connections version by navigating to the IBM/WebSphere console or checking the installation directory for version.info. Also verify via the About section in the Connections administration interface.Affected if The installed version is exactly 8.0 (match on = 8.0 from the affected versions)
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Identify user input entry pointsReview which Connections modules are enabled that accept user-generated content: Blogs, Forums, Wikis, Profiles, Activities, or Files. Check the Connections configuration files (connections-config.xml, widget-config.xml) for enabled features.Affected if Any of these features that accept user input are enabled and accessible to end users
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Verify input validation configurationExamine the WebSphere Application Server security settings and Connections configuration for input validation filters. Check if there are custom filters or validation rules configured in the ibm-web-bnd.xml or web.xml files.Affected if No input validation filters are configured, or default sanitization is disabled/missing
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Check Content Security Policy headersInspect HTTP response headers from Connections pages using browser dev tools or a tool like curl. Look for Content-Security-Policy or X-Content-Type-Options headers.Affected if CSP headers are missing or set to overly permissive values (like unsafe-inline for script sources)
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Test for reflected user input in common areasUse a test account to submit potentially malicious script payloads in visible profile fields, blog comments, forum posts, or status updates. Check if the input is rendered as-is without encoding.Affected if User-supplied content is displayed without HTML encoding or sanitization
A user is affected if they have HCL Connections version 8.0 running with any user input-accepting features enabled and without proper input validation or CSP protections in place.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataImplement proper input validation and output encoding for all user-supplied data; consider adding Content-Security-Policy headers to mitigate XSS execution.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-21788 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-21788 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data