CVE-2026-50179

@actual-app/web has CSV Formula Injection in Transaction Export via Imported Payee/Notes Fields

• Confidentiality: Adjacent transaction data (amounts, account names, balances, payees, categories) can be exfiltrated to attacker-controlled URLs through =HYPERLINK clicks or auto-firing =WEBSERVICE/=IMPORTXML.
• Integrity: Spreadsheet recipients (accountants, tax preparers) see attacker-chosen display values where they expected raw payee names, enabling fraud (e.g., forged "Refund" line items linking to phishing).
• Reach: Exports from Actual Budget are commonly shared with third parties (accountants, tax software, household members). One malicious imported statement contaminates every future export of that budget.
• Note on AC:H: requires victim-driven import → export → spreadsheet open. Modern Excel disables DDE by default, narrowing the RCE pathway, but =HYPERLINK exfil is universal and silent.

CVE-2026-50179 has a CVSS score of 4.2 (Medium). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (26.6.0); upgrading removes the vulnerable code path.

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Pass a cast.string callback to csv-stringify that prefixes any formula-trigger string with a single quote, the OWASP-recommended neutralization. Apply at both call sites in packages/loot-core/src/server/transactions/export/export-to-csv.ts:

import { stringify as csvStringify } from 'csv-stringify/sync';

const FORMULA_PREFIX = /^[=+\-@\t\r]/;

function neutralizeFormula(value: string): string {
  return FORMULA_PREFIX.test(value) ? `'${value}` : value;
}

const csvOptions = {
  header: true,
  cast: {
    string: (value: string) => neutralizeFormula(value),
  },
} as const;

// export-to-csv.ts:56
return csvStringify(transactionsForExport, csvOptions);

// export-to-csv.ts:131
return csvStringify(transactionsForExport, csvOptions);

Alternative defenses to consider in addition:

• Strip/neutralize formula prefixes on import in parse-file.ts for payee_name/notes so the database never contains formula-shaped strings (defense in depth, protects any future export consumers).
• Add a regression unit test that asserts every CSV cell starting with =, +, -, @, \t, or \r is prefixed with '.

1. What is CVE-2026-50179? CVE-2026-50179 is a medium-severity security vulnerability in @actual-app/web (npm), affecting versions < 26.6.0. It is fixed in 26.6.0.
2. How severe is CVE-2026-50179? CVE-2026-50179 has a CVSS score of 4.2 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of @actual-app/web are affected by CVE-2026-50179? @actual-app/web (npm) versions < 26.6.0 is affected.
4. Is there a fix for CVE-2026-50179? Yes. CVE-2026-50179 is fixed in 26.6.0. Upgrade to this version or later.
5. Is CVE-2026-50179 exploitable, and should I be worried? Whether CVE-2026-50179 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-50179 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-50179? Upgrade @actual-app/web to 26.6.0 or later.