CVE-2026-3404
Published: 02 March 2026
Summary
CVE-2026-3404 is a low-severity Externally Controlled Reference to a Resource in Another Sphere (CWE-610) vulnerability in Jeesite Jeesite. Its CVSS base score is 2.3 (Low).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 26.7th 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 are NIST 800-53 SI-10 (Information Input Validation) and AC-4 (Information Flow Enforcement).
Deeper analysis
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.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-9137
Vulnerability details
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…
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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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
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.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly requires validation and sanitization of XML input to block external entity declarations before they reach the vulnerable CasOutHandler.java parser.
Enforces information flow rules that can prohibit resolution of external entities from untrusted remote sources into the Endpoint component.
Enables monitoring of XML parsing behavior and anomalous external entity references that would indicate exploitation attempts against the published CVE-2026-3404 vector.