Vulnerability in Arp242 Goatcounter
CVE-2026-108740
GoatCounter through 2.7.0 contains a mass assignment privilege escalation vulnerability in the userPrefSave handler that allows logged-in users to modify protected account fields via form-encoded requests. Attackers with read-only access can POST user.access[all]=* and user.email_verified=true to /user/pref, bypassing readonly tags to gain superuser or admin access.
Vulnerability class: Mass Assignment
Published .
CVSS v3 metric
CVSS v3 base score 8.3 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- hackmd.io/@haind03/goatcounter-user-pref-access-mass-assignment-20261011 (third-party-advisory)
- github.com/arp242/goatcounter/blob/7e91d8a9bdbb0dd48496e498c5680f8f3477a1b4/han… (technical-description)
- github.com/arp242/goatcounter/blob/7e91d8a9bdbb0dd48496e498c5680f8f3477a1b4/use… (technical-description)
- github.com/arp242/goatcounter (product)
- www.vulncheck.com/advisories/goatcounter-through-2.7.0-privilege-escalation-via… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-108740?
- CVE-2026-108740 is a high-severity vulnerability in Arp242 Goatcounter, classified under Improperly Controlled Modification of Dynamically-Determined Object Attributes. CVSS score: 8.3/10. Published 2026-10-11.
- How severe is CVE-2026-108740?
- High severity. CVSS v3 base score is 8.3 out of 10.