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PatchSiren cyber security CVE debrief

CVE-2026-19505 RDK CVE debrief

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-08-19T20:17:14.150Z and has not been modified since then. The vulnerability, CVE-2026-19505, involves improper cryptographic signature verification in `jst_functions.c` of RDK-B WebUI `rdkb-2025q4-kirkstone.04.10.26`, allowing remote attackers to bypass authentication via a forged JWT with an invalid RSA signature. This critical vulnerability affects the authentication mechanism of RDK-B WebUI, potentially allowing unauthorized administrative access. Evidence is limited to public sources and may not reflect the full scope or impact. Defenders should verify affected systems and review authentication mechanisms.

Vendor
RDK
Product
RDK-B WebUI
CVSS
CRITICAL 9.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-08-19
Original CVE updated
2026-09-03
Advisory published
2026-08-19
Advisory updated
2026-09-03

Who should care

Administrators and users of RDK-B WebUI, especially those with administrative access, should be aware of this critical vulnerability and take immediate action to secure their systems. This includes reviewing authentication mechanisms, implementing proper cryptographic signature verification for JWT, and restricting access to administrative interfaces. Security teams should prioritize patching or mitigating this vulnerability to prevent potential unauthorized access.

Technical summary

The CVE-2026-19505 vulnerability is caused by improper cryptographic signature verification in `jst_functions.c` of RDK-B WebUI `rdkb-2025q4-kirkstone.04.10.26`. This allows a remote attacker to bypass authentication and obtain administrative access via a forged JWT containing an invalid RSA signature. The vulnerability affects the authentication mechanism of RDK-B WebUI, potentially allowing unauthorized administrative access.

Defensive priority

Critical vulnerability in RDK-B WebUI authentication

Recommended defensive actions

  • Review and verify authentication mechanisms in RDK-B WebUI
  • Implement proper cryptographic signature verification for JWT
  • Restrict access to administrative interfaces
  • Monitor for suspicious authentication attempts
  • Update to the latest version of RDK-B WebUI if available

Evidence notes

The CVE-2026-19505 record indicates improper cryptographic signature verification in `jst_functions.c` of RDK-B WebUI `rdkb-2025q4-kirkstone.04.10.26`, allowing remote attackers to bypass authentication via a forged JWT with an invalid RSA signature. Official CVE and NVD records provide details. Evidence is limited to public sources and may not reflect the full scope or impact. Defenders should verify affected systems and review authentication mechanisms.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-19505 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-19505

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-19505 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-19505

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.