CVE-2026-65603: Privilege Escalation (CVSS 8.8)

Description

The Grav Login plugin (grav-plugin-login) versions <= 3.8.11 contain a privilege escalation flaw in the authenticated profile self-update handler (processUserProfile(), the update_user task). Unlike the registration handler, this handler does not strip privilege fields ('groups','access') from user-submitted form data before persisting them. When an administrator has added 'groups' and/or 'access' to plugins.login.user_registration.fields and the default 'regular'/DataUser account backend is in use, a low-privilege authenticated user can POST crafted profile form data (e.g. access[admin][super]=true) to escalate to super-admin, enabling admin panel access, scheduler abuse (RCE), and Twig evaluation. Fixed in 3.8.12.

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CVSS v3.1 Score

8.8

HIGH

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

EPSS — Exploit Prediction

0.0030

Probability of exploitation

0.23%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-269 CWE-269

References

Other References

https://github.com/getgrav/grav/security/advisories/GHSA-h33v-82r9-v8pm https://www.vulncheck.com/advisories/grav-login-plugin-privilege-escalation-via-profile-update https://github.com/getgrav/grav/security/advisories/GHSA-h33v-82r9-v8pm

Frequently Asked Questions

What is CVE-2026-65603? +

The Grav Login plugin (grav-plugin-login) versions <= 3.8.11 contain a privilege escalation flaw in the authenticated profile self-update handler (processUserProfile(), the update_user task). Unlike the registration handler, this handler does not strip privilege fields ('groups','access') from user-submitted form data before persisting them. When an administrator has added 'groups' and/or 'access' to plugins.login.user_registration.fields and the default 'regular'/DataUser account backend is in use, a low-privilege authenticated user can POST crafted profile form data (e.g. access[admin][super]=true) to escalate to super-admin, enabling admin panel access, scheduler abuse (RCE), and Twig evaluation. Fixed in 3.8.12. It has a CVSS v3.1 base score of 8.8 (HIGH).

How severe is CVE-2026-65603? +

CVE-2026-65603 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0030, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-65603? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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