CVE-2026-49979: CWE-209: Generation of Error Message Containing Sensitive Information in appsmithorg appsmith
Appsmith is a platform to build admin panels, internal tools, and dashboards. Prior to 1.99, the POST /api/v1/admin/send-test-email endpoint accepts attacker-controlled smtpHost and smtpPort values and establishes a raw JavaMail TCP connection without any IP validation. This completely bypasses WebClientUtils.IP_CHECK_FILTER, which only applies to Spring WebClient HTTP requests. Additionally, the raw MailException.getMessage() is returned verbatim in the API error response, enabling error-based internal port scanning and service banner enumeration. This vulnerability is fixed in 1.99.
AI Analysis
Technical Summary
The vulnerability in appsmith (CVE-2026-49979) affects versions before 1.99. The POST /api/v1/admin/send-test-email endpoint accepts attacker-controlled smtpHost and smtpPort values and establishes a raw JavaMail TCP connection without IP validation, bypassing the WebClientUtils.IP_CHECK_FILTER which only applies to HTTP requests. The raw error message from MailException.getMessage() is returned in API error responses, allowing error-based internal port scanning and service banner enumeration. This information disclosure and bypass of IP filtering can aid attackers in reconnaissance. The vulnerability is addressed in version 1.99.
Potential Impact
An attacker with high privileges can supply arbitrary SMTP host and port values to the vulnerable endpoint, bypassing IP filtering controls and causing the application to make raw TCP connections. The application returns detailed error messages containing sensitive information, enabling internal port scanning and service banner enumeration. This can facilitate further attacks by revealing internal network details. The CVSS score is 5.1 (medium severity), reflecting the moderate impact of information disclosure and bypass of IP filtering.
Mitigation Recommendations
Upgrade appsmith to version 1.99 or later, where this vulnerability is fixed. There is no indication of a temporary workaround or alternative mitigation. Patch status is confirmed fixed in 1.99.
CVE-2026-49979: CWE-209: Generation of Error Message Containing Sensitive Information in appsmithorg appsmith
Description
Appsmith is a platform to build admin panels, internal tools, and dashboards. Prior to 1.99, the POST /api/v1/admin/send-test-email endpoint accepts attacker-controlled smtpHost and smtpPort values and establishes a raw JavaMail TCP connection without any IP validation. This completely bypasses WebClientUtils.IP_CHECK_FILTER, which only applies to Spring WebClient HTTP requests. Additionally, the raw MailException.getMessage() is returned verbatim in the API error response, enabling error-based internal port scanning and service banner enumeration. This vulnerability is fixed in 1.99.
CVSS v4.0
Score 5.1medium
Affected software
pkg:github/appsmithorg/appsmithRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in appsmith (CVE-2026-49979) affects versions before 1.99. The POST /api/v1/admin/send-test-email endpoint accepts attacker-controlled smtpHost and smtpPort values and establishes a raw JavaMail TCP connection without IP validation, bypassing the WebClientUtils.IP_CHECK_FILTER which only applies to HTTP requests. The raw error message from MailException.getMessage() is returned in API error responses, allowing error-based internal port scanning and service banner enumeration. This information disclosure and bypass of IP filtering can aid attackers in reconnaissance. The vulnerability is addressed in version 1.99.
Potential Impact
An attacker with high privileges can supply arbitrary SMTP host and port values to the vulnerable endpoint, bypassing IP filtering controls and causing the application to make raw TCP connections. The application returns detailed error messages containing sensitive information, enabling internal port scanning and service banner enumeration. This can facilitate further attacks by revealing internal network details. The CVSS score is 5.1 (medium severity), reflecting the moderate impact of information disclosure and bypass of IP filtering.
Mitigation Recommendations
Upgrade appsmith to version 1.99 or later, where this vulnerability is fixed. There is no indication of a temporary workaround or alternative mitigation. Patch status is confirmed fixed in 1.99.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-02T18:30:51.282Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a3c5afe4853345fc1f1082c
Added to database: 06/24/2026, 22:32:30 UTC
Last enriched: 07/02/2026, 22:35:42 UTC
Last updated: 08/08/2026, 12:41:11 UTC
Views: 91
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