VulnerabilityPublished 11 Mar 2026

CVE-2026-3962: Jcharis Machine-Learning-Web-Apps · Cross-site Scripting

Affects Jcharis Machine-Learning-Web-AppsSource CVE Database V5

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Public exploit available · CVSS 5.3 Medium.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 4.0 base score

5.3Medium

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

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

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

Base metrics

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: Passive
Vulnerable system confidentiality: None
Vulnerable system integrity: Low
Vulnerable system availability: None
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: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
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: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: Passive: Successful exploitation of this vulnerability requires limited interaction by the targeted user with the vulnerable system and the attacker’s payload. These interactions would be considered involuntary and do not require that the user actively subvert protections built into the vulnerable system.
Vulnerable system confidentiality: None: There is no loss of confidentiality within 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: None: There is no impact to availability within 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 11 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 30 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
JcharisMachine-Learning-Web-Apps	Affected =a6996b634d98ccec4701ac8934016e8175b60eb5	Fixed in–

AI-suggested

Organizations should implement strict input validation and output encoding on all user-supplied data before it reaches the template rendering engine to mitigate this XSS vulnerability. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of potential XSS attacks. Monitor web application logs and user activity for signs of exploitation attempts or anomalous behavior. Consider deploying web application firewalls (WAFs) with rules tailored to detect and block XSS payloads targeting the affected endpoints. Engage with the vendor or community to track updates or patches addressing this issue. Educate users about the risks of clicking untrusted links or interacting with suspicious content to reduce the likelihood of successful exploitation. Finally, review and harden the deployment environment to minimize the potential damage from successful attacks, including restricting permissions and isolating critical systems.

Description

CVE-2026-3962 is a medium-severity cross-site scripting (XSS) vulnerability in Jcharis Machine-Learning-Web-Apps, specifically in the render_template function of the Jinja2 template handler. The flaw allows remote attackers to inject malicious scripts without authentication, requiring user interaction to trigger. The vulnerability arises from improper sanitization of inputs passed to the Jinja2 template rendering process. Although no patch or updated version is currently available due to the product's rolling release model and lack of vendor response, a public exploit exists. This vulnerability can lead to session hijacking, credential theft, or unauthorized actions performed in the context of the victim's browser. Organizations using this product should prioritize input validation and consider temporary mitigations until an official fix is released. Countries with significant adoption of this product or strategic interest in machine learning web applications are at higher risk. The CVSS 4.0 score is 5.3, reflecting medium severity due to remote exploitability but requiring user interaction and limited impact on confidentiality and integrity.

Impact

The impact of CVE-2026-3962 on organizations worldwide includes potential compromise of user sessions, theft of sensitive information such as authentication tokens or personal data, and unauthorized actions performed on behalf of users. This can lead to reputational damage, loss of user trust, and potential regulatory consequences if personal data is exposed. Since the vulnerability is in a machine-learning web application framework, organizations relying on this product for deploying ML models or services may face disruption or data integrity issues if attackers manipulate the application interface. The remote exploitability without authentication increases the attack surface, especially for publicly accessible deployments. However, the requirement for user interaction and the medium severity score suggest that while impactful, the threat is not critical but still significant enough to warrant prompt attention. The lack of vendor response and patch availability prolongs exposure, increasing risk over time. Attackers could leverage this vulnerability as an initial foothold or pivot point in broader attack campaigns targeting organizations using this software.

Summary

CVE-2026-3962 identifies a cross-site scripting vulnerability in the Jcharis Machine-Learning-Web-Apps project, specifically within the render_template function located in the app.py file under the Jinja2 template handler component. The vulnerability stems from insufficient input sanitization or improper handling of user-supplied data before rendering templates, enabling attackers to inject malicious JavaScript code. This flaw can be exploited remotely without authentication, but it requires user interaction to trigger the malicious payload, such as clicking a crafted link or visiting a malicious page. The public availability of an exploit increases the risk of exploitation in the wild. The vulnerability's CVSS 4.0 score of 5.3 indicates a medium severity level, reflecting its network attack vector, low complexity, no privileges required, but requiring user interaction and having limited impact on confidentiality and integrity. The vulnerability could allow attackers to perform actions such as session hijacking, stealing sensitive information, or conducting phishing attacks by injecting malicious scripts into web pages rendered by the affected application.

References

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