CVE-2026-42840
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 · uneditedAn authenticated user can persist arbitrary HTML/JavaScript in the email_id or mobile_no fields of a Customer record and trigger unescaped rendering in the Point of Sale (POS) interface for every operator who selects that customer. This issue affects ERPNext: 16.16.0.
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 · high confidenceThis is a stored Cross-Site Scripting (XSS) vulnerability in ERPNext's Point of Sale interface. An authenticated user can inject malicious HTML/JavaScript into the email_id or mobile_no fields of a Customer record, which then executes in the browsers of all POS operators who select that customer, due to unescaped rendering of these fields.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS 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
- Authentication
- X
- User interaction
- P
- Scope
- X
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
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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Identify ERPNext installation and versionAccess the ERPNext system via the command line (bench version) or check the About section in the Frappe/ERPNext UI. Compare the installed version to any official ERPNext release notes.Affected if The installed ERPNext version falls within the vulnerable version range (if known) or is an unpatched version.
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Verify POS module is enabledLog in as Administrator, navigate to the Modules section, or use the bench command: bench get-app erpnext and check module list. Verify if Point of Sale (POS) is listed as an active module.Affected if The POS module is installed and accessible to users, making the XSS payload executable path available.
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Check for Customer records with injected payloadsAccess the Customer list doctype (via: /app/customer or bench --site [sitename] execute frappe.call --method=frappe.boot.get_allow_docs) and review the email_id and mobile_no fields for any suspicious patterns (e.g., <script>, javascript:, onerror=, img src=x onerror=). Use a database query if direct access is available: SELECT name, email_id, mobile_no FROM tabCustomer WHERE email_id LIKE '%<%' OR mobile_no LIKE '%<%';Affected if Customer records exist where email_id or mobile_no fields contain unescaped HTML/JavaScript characters (<, >, script tags, event handlers).
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Inspect user roles with Customer write accessGo to Role and Role Profile management (via /app/role or /app/role-profile) and identify which roles have Create, Write, or Edit permissions on the Customer doctype. Check User records to see which authenticated users hold these roles.Affected if Authenticated users with Customer creation/editing permissions exist in the system, allowing them to inject the malicious payload.
Your environment is affected if ERPNext is running, the POS module is active, and Customer records exist with unsanitized input in email_id or mobile_no fields that could be rendered when POS operators view those customers.
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 output encoding/escaping for the email_id and mobile_no fields when rendered in the POS interface, and add input validation to reject HTML/JavaScript in these fields at the point of entry.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-42840 — 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-2026-42840 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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- Version or environment caveats, and links to real fixes
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