CVE-2026-36537

Description

ThingsBoard v4.3.0.1 is vulnerable to an authentication bypass during the OAuth authorization code exchange. The application improperly trusts user-supplied identity data within the user parameter of the /login/oauth2/code/ endpoint. By manipulating the email address in this JSON object, a remote attacker can bypass authentication and gain full access to any existing user account on the platform without possessing the target user's credentials. This results in a complete account takeover.

CVSS v3.1 Score

9.8

CRITICAL

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

EPSS — Exploit Prediction

0.0051

Probability of exploitation

0.40%

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-290 CWE-290

References

Other References

https://gist.github.com/KKC73/b9d4efda05693882f1e613c0e0fac78d https://gist.github.com/KKC73/b9d4efda05693882f1e613c0e0fac78d

Frequently Asked Questions

What is CVE-2026-36537? +

ThingsBoard v4.3.0.1 is vulnerable to an authentication bypass during the OAuth authorization code exchange. The application improperly trusts user-supplied identity data within the user parameter of the /login/oauth2/code/ endpoint. By manipulating the email address in this JSON object, a remote attacker can bypass authentication and gain full access to any existing user account on the platform without possessing the target user's credentials. This results in a complete account takeover. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-36537? +

CVE-2026-36537 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0051, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-36537? +

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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