CVE-2026-19505: Rdk Rdk-B Webui

Critical severity, CVSS 9.8. EPSS: 0.4% chance of exploitation in the next 30 days.

Improper cryptographic signature verification in `jst_functions.c` in RDK-B WebUI `rdkb-2025q4-kirkstone.04.10.26` allows a remote attacker to bypass authentication and obtain administrative access via a forged JWT containing an invalid RSA signature.

Affected products

• Rdk Rdk-B Webui

Published 2026-08-19. Last modified 2026-09-03.