CVE-2026-3404

MediumPublic PoC

Published: 02 March 2026

Published

02 March 2026

Modified

09 March 2026

KEV Added

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Patch

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CVSS Score 5.0 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L

EPSS Score 0.0004 13.4th percentile

Risk Priority 10 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-3404 is a medium-severity Externally Controlled Reference to a Resource in Another Sphere (CWE-610) vulnerability in Jeesite Jeesite. Its CVSS base score is 5.0 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 13.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190) and 1 other technique.

Threat & Defense Details

Likely Mitigating ControlsAI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

CA-8 Penetration Testing

addresses: CWE-611

Penetration testing includes XML external entity payloads, detecting XXE vulnerabilities and enabling their mitigation.

SI-22 Information Diversity

addresses: CWE-610

Limits impact of an externally controlled reference to a primary information resource by switching to an identified alternative.

SI-4 System Monitoring

addresses: CWE-611

Identifies XML external entity processing via monitoring of unusual file/network access or resource usage.

MITRE ATT&CK Enterprise TechniquesAI

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 →

T1005 Data from Local System Collection

Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.

attack.mitre.org →

Why these techniques?

XXE in public-facing web endpoint (CasOutHandler) directly enables exploitation via T1190; classic XXE file read capability facilitates T1005 for limited local data disclosure.

Confidence: MEDIUM · MITRE ATT&CK Enterprise v18.1

NVD Description

A flaw has been found in thinkgem JeeSite up to 5.15.1. Impacted is an unknown function of the file /com/jeesite/common/shiro/cas/CasOutHandler.java of the component Endpoint. Executing a manipulation can lead to xml external entity reference. The attack may be performed from…

remote. Attacks of this nature are highly complex. The exploitability is considered difficult. The exploit has been published and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

Deeper analysisAI

CVE-2026-3404 is a vulnerability in thinkgem JeeSite versions up to 5.15.1, affecting an unknown function in the file /com/jeesite/common/shiro/cas/CasOutHandler.java of the Endpoint component. The flaw enables XML external entity (XXE) reference attacks, corresponding to CWEs CWE-610 and CWE-611. Published on 2026-03-02, it carries a CVSS v3.1 base score of 5.0 (AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L).

A remote attacker with low privileges (PR:L) can exploit this issue via a highly complex manipulation requiring high attack complexity (AC:H). Successful exploitation leads to low impacts on confidentiality, integrity, and availability, such as limited data disclosure, modification, or denial of service. Exploitability is considered difficult.

Advisories from VulDB indicate that an exploit has been published and may be used, with references including https://vuldb.com/?ctiid.348299, https://vuldb.com/?id.348299, https://vuldb.com/?submit.763732, and https://www.yuque.com/la12138/pa2fpb/ew8x2qss8dv0bsu0?singleDoc. The vendor was contacted early about the disclosure but did not respond in any way, and no patches or mitigations are mentioned.