CVE-2026-4990
Published: 27 March 2026
Summary
CVE-2026-4990 is a medium-severity Incorrect Privilege Assignment (CWE-266) vulnerability. Its CVSS base score is 6.9 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 17.1th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 AC-3 (Access Enforcement) and SI-10 (Information Input Validation).
Deeper analysis
CVE-2026-4990 is an improper authorization vulnerability affecting Chatwoot versions up to 4.11.1. The issue resides in an unknown function within the /app/login file of the Signup Endpoint component, where manipulation of the signupEnabled argument to true bypasses authorization controls. This flaw, linked to CWEs-266 (Incorrect Privilege Assignment) and CWE-285 (Improper Authorization), carries a CVSS v3.1 base score of 7.3 (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L), indicating high severity due to its network-accessible nature and lack of prerequisites.
The vulnerability enables remote exploitation by unauthenticated attackers with low complexity and no user interaction required. Successful exploitation allows limited impacts on confidentiality, integrity, and availability, potentially permitting unauthorized actions such as improper account creation or access via the signup process.
VulDB advisories, referenced at https://vuldb.com/?ctiid.353877, https://vuldb.com/?id.353877, and https://vuldb.com/?submit.772515, detail the issue and note that the exploit has been publicly disclosed and may be actively used. The vendor was notified early but provided no response, and no patches or mitigations are mentioned in available sources.
The exploit's public disclosure heightens the risk of real-world abuse against unpatched Chatwoot instances.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-16896
Vulnerability details
A security vulnerability has been detected in chatwoot up to 4.11.1. The affected element is an unknown function of the file /app/login of the component Signup Endpoint. Such manipulation of the argument signupEnabled with the input true leads to improper…
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authorization. The attack can be executed remotely. The exploit has been disclosed publicly and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Public-facing web app authorization bypass in signup endpoint directly enables remote exploitation (T1190) and facilitates unauthorized account creation (T1136).
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Enforces approved authorizations for access to the signup endpoint, directly preventing bypass via manipulation of the signupEnabled parameter.
Validates and sanitizes inputs to the signup endpoint, blocking unauthorized manipulation of the signupEnabled argument to true.
Requires timely remediation of the specific software flaw in Chatwoot's signup endpoint causing improper authorization.