Escape spreadsheet formulas when exporting visits as CSV - #2665
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User-Agent and Referer are set by whoever visits a short URL, and were written verbatim to the CSV produced by the visits commands, so values starting with =, -, +, @, tab or CR were evaluated as formulas when the file was opened in a spreadsheet (CVE-2026-18738). Enable league/csv's EscapeFormula formatter, which prefixes those values with a single quote. All visits commands render CSV through VisitsCommandUtils::renderOutput, so this covers short-url:visits, domain:visits, tag:visits, visit:orphan and visit:non-orphan. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
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Can you just consider the fix for the future? |
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User-AgentandRefererare stored verbatim and written as-is by the--format=csvvisitcommands. A value starting with
=,-,+or@is interpreted as a formula by Excel andGoogle Sheets, so a visitor can plant one with no authentication and it runs on the machine of
whoever opens the export. In Google Sheets,
IMPORTXML/IMPORTDATAfetch without any userinteraction.
This is CVE-2026-18738, which is already public. I'm opening a PR rather than a report because
there is nothing left to disclose and
SECURITY.mdasks not to file public issues.league/csvalready shipsEscapeFormulafor exactly this, so the fix is enabling it inVisitsCommandUtils::renderCSVOutput:No new dependency, no behaviour change for ordinary values.
Before:
After:
This covers every visit command, since they all go through
VisitsCommandUtils::renderOutput:short-url:visits,domain:visits,tag:visits,visit:orphanandvisit:non-orphan.Verified against 5.1.7 by planting the payloads through a real visit and exporting; a normal
Mozilla/5.0value comes out untouched. Test included.