CVE-2026-129427
Deferred Deferred - Pending Action

Stored XSS via Avatar Upload in Cervantes v1.3-beta

Publication date: 2026-11-14

Last updated on: 2026-11-14

Assigner: Grayback

Description
Stored XSS via avatar upload chained with an authentication bypass in /Attachments leads to ATO in Cervantes version v1.3-beta could allow an attacker to execute arbitrary code in another user's browser with elevated privileges

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Meta Information

Published
2026-11-14
Last Modified
2026-11-14
Generated
2026-11-15
AI Q&A
2026-11-14
EPSS Evaluated
N/A
NVD
CVE-2026-129427
EUVD
EUVD-2026-125897

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
grayback jiracontroller *

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-79 The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

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Executive Summary

This vulnerability is a stored cross-site scripting (XSS) flaw via avatar upload combined with an authentication bypass in the /Attachments endpoint of Cervantes version v1.3-beta. It allows an attacker to chain these issues to achieve account takeover (ATO) by executing arbitrary code in another user's browser with elevated privileges.

Detection Guidance

To detect this vulnerability, inspect uploaded avatar files for malicious scripts or unexpected content types. Check Cervantes version v1.3-beta for authentication bypass flaws in /Attachments. Monitor network traffic for unauthorized access attempts or unusual file uploads.

Impact Analysis

An attacker could exploit this to gain unauthorized access to user accounts, steal sensitive data, perform actions on behalf of users, or escalate privileges within the application. This could lead to data breaches, unauthorized modifications, or further compromise of the system.

Compliance Impact

This vulnerability could lead to unauthorized access to personal or sensitive data, violating GDPR's data protection principles and HIPAA's security requirements. Non-compliance may result in legal penalties, fines, or reputational damage due to data exposure.

Mitigation Strategies

Update Cervantes to the latest version to patch the stored XSS and authentication bypass vulnerabilities. Review and restrict avatar upload permissions to trusted users only. Implement input validation for file uploads and sanitize user-generated content.

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