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Vulnerability record · CVE-2026-19505 · published 19 August 2026

CVE-2026-19505: Improper verification of cryptographic signature vulnerability

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.

9.8 CVSS 3.1 Critical EPSS 0.37% · top 72.1% CWE-347 · Improper verification of cryptographic signature Awaiting Analysis
9.8CVSS 3.1 base score
0.37%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
2References
3 Sep 2026Last modified by NVD

Description

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.

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

References

LinkTags
https://developer.rdkcentral.com/documentation/documentation/rdk_broadband_documentation/components/webui/
https://whitehats.pwr.edu.pl//blog/2026-08-19-multiple-vulnerabilities-in-rdkb/

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Source: NIST National Vulnerability Database (record CVE-2026-19505), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.