5.4Medium
CVE-2026-86257
wger before 2.6 fails to sanitize first_name and last_name fields in the gym member TSV export endpoint, allowing any gym member to inject spreadsheet formulas. Attackers can inject formulas like =HYPERLINK to exfiltrate admin data or execute code when admins open the exported file in Excel or LibreOffice Calc.
What this means for your business
- An attacker can use it remotely, over a network, with an ordinary user login, but only after tricking someone into an action such as opening a file or a link.
- FIRST's prediction model gives it a 0.2% chance of attack attempts being seen in the next 30 days, ranking above 6% of all known flaws.
What to do
- 1Ask your IT team or provider whether any of your systems use the affected product.
- 2If you do, follow the vendor's guidance. No patch reference has been published yet.
Not sure if your company is exposed?
Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.
Scoring
- CVSS
- 5.4 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N- CVSS v4
- 4.8
- Weakness
- CWE-1236
- Assigned by
- disclosure@vulncheck.com
Dates
- Published
- 2026-09-06
- Last modified
- 2026-09-08
- Sources
- NVD