VulnerabilityPublished 2 Mar 2026

CVE-2026-3404: thinkgem JeeSite · XML External Entity Reference

Affects thinkgem JeeSiteSource CVE Database V5

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Public exploit available · CVSS 2.3 Low.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 4.0 base score

2.3Low

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 33% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P

Base metrics

Attack Vector: Network
Attack Complexity: High
Attack Requirements: None
Privileges Required: Low
User Interaction: None
Vulnerable system confidentiality: Low
Vulnerable system integrity: Low
Vulnerable system availability: Low
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Threat metrics

Exploit Maturity: POC

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: High: The successful attack depends on the evasion or circumvention of security-enhancing techniques in place that would otherwise hinder the attack. These include: Evasion of exploit mitigation techniques, for example, circumvention of address space randomization (ASLR) or data execution prevention (DEP) must be performed for the attack to be successful; Obtaining target-specific secrets. The attacker must gather some target-specific secret before the attack can be successful. A secret is any piece of information that cannot be obtained through any amount of reconnaissance. To obtain the secret the attacker must perform additional attacks or break otherwise secure measures (e.g. knowledge of a secret key may be needed to break a crypto channel). This operation must be performed for each attacked target.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Vulnerable System.
Vulnerable system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Vulnerable System.
Vulnerable system availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the Vulnerable System are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.
Exploit Maturity: POC: Based on threat intelligence sources each of the following must apply: · Proof-of-concept is publicly available · No knowledge of reported attempts to exploit this vulnerability · No knowledge of publicly available solutions used to simplify attempts to exploit the vulnerability

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 2 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: evidence found.
CVSS exploit maturity: proof of concept public
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CVSS vector, the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
thinkgemJeeSite	Affected =5.15.0 =5.15.1	Fixed in–
Maventhinkgem/jeesite`pkg:maven/thinkgem/jeesite`Other threats	Affected =5.15.0 =5.15.1	Fixed in–

CPE configurations (1)

cpe:2.3:a:jeesite:jeesite:*:*:*:*:*:*:*:*

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AI-suggested

To mitigate CVE-2026-3404, organizations should first verify if they are running affected versions (5.15.0 or 5.15.1) of thinkgem JeeSite and plan to upgrade to a fixed version once available. In the absence of an official patch, immediate mitigations include disabling external entity processing in XML parsers used by the application, which can be done by configuring the XML parser factory to disallow DOCTYPE declarations and external entity resolution. Implement strict input validation and sanitization for all XML inputs, especially those processed by the CasOutHandler endpoint. Employ network segmentation and firewall rules to restrict outbound traffic from application servers to prevent SSRF exploitation. Monitor logs for unusual XML payloads or errors related to XML parsing. Additionally, consider deploying Web Application Firewalls (WAFs) with custom rules to detect and block malicious XML requests. Engage with the vendor or community for updates and patches, and conduct regular security assessments to detect similar vulnerabilities.

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.

Impact

The primary impact of CVE-2026-3404 is the potential exposure of sensitive information through XML External Entity attacks, which can lead to unauthorized disclosure of internal files or data. Additionally, attackers might leverage this flaw to perform SSRF attacks, potentially accessing internal network resources or causing denial of service by exhausting system resources. However, the overall impact is limited by the high complexity of exploitation and the requirement for low-level privileges, reducing the likelihood of widespread abuse. Organizations using JeeSite versions 5.15.0 and 5.15.1 in critical environments may face risks to confidentiality and availability if this vulnerability is exploited. The lack of vendor response and absence of patches increase the window of exposure. While no known active exploitation has been reported, the public availability of an exploit increases the risk of future attacks, especially in targeted scenarios.

Summary

CVE-2026-3404 identifies an XML External Entity (XXE) vulnerability in thinkgem JeeSite, a Java-based web application framework, affecting versions 5.15.0 and 5.15.1. The vulnerability resides in an unspecified function within the file /com/jeesite/common/shiro/cas/CasOutHandler.java, part of the Endpoint component. XXE vulnerabilities occur when XML parsers process external entity references without proper validation or disabling, allowing attackers to read arbitrary files, perform server-side request forgery (SSRF), or cause denial of service by exhausting resources. In this case, remote attackers can manipulate XML input to trigger external entity resolution. The attack complexity is high, meaning exploitation requires detailed knowledge of the system and crafting of specific XML payloads. No user interaction is needed, but low privileges are required, indicating that an attacker must have some level of access to send crafted requests. The vendor was notified early but did not respond, and no patches have been published. The CVSS 4.0 vector indicates network attack vector, high complexity, no privileges required (PR:L suggests low privileges), no user interaction, and low impact on confidentiality, integrity, and availability. Although an exploit is publicly available, no confirmed exploitation in the wild has been reported. This vulnerability highlights the risk of insecure XML parsing in Java applications and the importance of secure coding practices and input validation.

References

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