Cyber Resilience

CVE-2026-49979

SSRF in Appsmith ≤ 1.99

Public PoCSSRFInfo Disclosure
Published
24 June 2026
Modified
29 June 2026
CVSS Score v4 5.1
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0025 17th percentile
Risk Priority 23 floored blend · peak EPSS

Summary

CVE-2026-49979 is a medium-severity Generation of Error Message Containing Sensitive Information (CWE-209) vulnerability in Appsmith Appsmith. Its CVSS base score is 5.1 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Software (T1592.002); ranked at the 17th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to AC-4 (Information Flow Enforcement) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access ControlA10:2025 Mishandling of Exceptional Conditions

EU & UK References

Vulnerability Data

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,…

more

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.

CWE(s)
CWE-209CWE-918

Related Threats

MITRE ATT&CK Enterprise Techniques

T1592.002 Software Reconnaissance
Adversaries may gather information about the victim's host software that can be used during targeting.
attack.mitre.org →
T1082 System Information Discovery Discovery
An adversary may attempt to get detailed information about the operating system and hardware, including version, patches, hotfixes, service packs, and architecture.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1592 Gather Victim Host Information Reconnaissance
Adversaries may gather information about the victim's hosts that can be used during targeting.
attack.mitre.org →
T1595 Active Scanning Reconnaissance
Adversaries may execute active reconnaissance scans to gather information that can be used during targeting.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-51408Same product: Appsmith Appsmith
CVE-2026-55455Same product: Appsmith Appsmith
CVE-2026-50189Same product: Appsmith Appsmith
CVE-2026-34411Same product: Appsmith Appsmith
CVE-2026-24042Same product: Appsmith Appsmith
CVE-2026-30862Same product: Appsmith Appsmith
CVE-2026-7299Same product: Appsmith Appsmith
CVE-2026-55454Same product: Appsmith Appsmith
CVE-2026-22794Same product: Appsmith Appsmith
CVE-2024-55965Same product: Appsmith Appsmith

Affected Assets

appsmith
appsmith
≤ 1.99

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V16.5.1
  • V1.3.6
  • V1.5.3
  • V5.3.2

Mitigating Controls (NIST 800-53 r5) AI

SI-11 Error Handling good match

si-11 directly requires error messages to avoid revealing exploitable information about the system or its data.

AC-4 Information Flow Enforcement good match

Information flow enforcement can restrict which destinations the server is allowed to contact on behalf of users.

SI-10 Information Input Validation good match

Input validation directly stops untrusted URLs from being accepted and fetched without destination checks.

SC-7 Boundary Protection partial match

Boundary protection limits the network reach of server-initiated requests even if SSRF occurs.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require sanitized error handling to prevent sensitive data disclosure.

DE.CM-09 partial match
prevents

Runtime monitoring of web applications and services can detect anomalous outbound requests indicative of SSRF.

ID.RA-01 partial match
prevents

Vulnerability identification processes can discover and record SSRF flaws in web applications.

PR.IR-01 partial match
prevents

Network segmentation and egress controls can limit the damage from successful SSRF requests.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.28 Secure coding mostly match
prevents

Secure coding standards explicitly forbid exposing sensitive data in errors.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing can detect error messages that leak sensitive information.

A.5.7 Threat intelligence partial match
prevents

Operational threat data describing SSRF campaigns can be used to tighten outbound-request allow-lists and detection rules before attackers exploit them.

A.8.15 Logging partial match
degrades

Logging policy can require suppression of sensitive data in error messages.

A.8.25 Secure development life cycle partial match
prevents

Secure SDLC mandates error-handling rules that avoid leaking sensitive information.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify safe error messaging.

References