CVE-2026-21889 is a vulnerability in Weblate, a web-based localization tool. This vulnerability allows unauthorized users to access sensitive screenshot images served directly by the HTTP server without proper access control. Specifically, prior to version 5.15.2, these images could be accessed by guessing their filenames, leading to the exposure of potentially sensitive information. Given its nature, the severity of this vulnerability is classified as low, with a CVSS score of 2.3.
The risk to organizations includes unauthorized access to sensitive content that may lead to privacy violations or data leakage. Although the attack complexity is high and requires some level of knowledge to exploit, the implications of such unauthorized access can still be severe, particularly for organizations that rely on Weblate for localization in sensitive projects.
As of the last update on January 23, 2026, there are no known public exploits for this vulnerability, and it has not been included in the Known Exploited Vulnerabilities (KEV) catalog. However, organizations are encouraged to patch their systems to version 5.15.2 or later to eliminate this risk.
Organizations should prioritize patching immediately.
Vulnerability Details
This vulnerability is classified under the Common Weakness Enumeration (CWE) as CWE-284, indicating improper access control. The vulnerability was discovered in versions of Weblate prior to 5.15.2, and it was published on January 14, 2026.
The CVSS score of 2.3 indicates a low severity vulnerability, with the attack vector being network-based and a high attack complexity. This means that while the vulnerability is technically exploitable, the effort required to exploit it is significant, requiring low privileges and no user interaction.
Technical Analysis
The root cause of this vulnerability stems from the lack of proper access controls on screenshot images served by the HTTP server. Attackers may leverage this weakness by guessing the filenames of these images. The attack vector is network-based, meaning an attacker does not need to be on the local network to exploit the vulnerability. However, the attack complexity is high, as it requires knowledge of the file naming conventions used by the application.
Since the vulnerability does not require user interaction, an attacker could potentially automate the filename guessing process, posing a risk of information disclosure. The confidentiality impact is low, with no integrity or availability impacts defined, as the vulnerability does not affect the application's operation but rather exposes specific files.
Risk & Impact Analysis
The real-world deployment risk of CVE-2026-21889 pertains to its potential to expose sensitive screenshot data. Organizations that utilize Weblate for localization should consider the implications of unauthorized access to these images, as they may contain confidential information. With a CVSS score of 2.3, the urgency to address this vulnerability is classified as low; however, organizations should still schedule remediation to mitigate any potential risks.
The blast radius is limited to Weblate installations running versions prior to 5.15.2, and as such, the vulnerability may not have widespread impact. Nevertheless, organizations should prioritize patching to ensure that their systems are secure.
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The versions of Weblate affected by this vulnerability are all prior to 5.15.2. Organizations running Weblate should ensure that they upgrade to this version or later to mitigate the risk.
Mitigation & Remediation
To mitigate the risk associated with CVE-2026-21889, organizations should upgrade to Weblate version 5.15.2 or later. If upgrading is not immediately possible, organizations should consider implementing access controls to restrict access to screenshot images based on user authentication status.
In addition to patching, organizations may benefit from reviewing their overall security posture and conducting a security assessment. For further insights on securing applications, organizations may consider engaging in application security assessment to identify any other vulnerabilities in their systems.
Detection Guidance
Organizations should monitor their logs for any unauthorized access attempts to screenshot images. Behavioral anomalies, such as unusual access patterns or requests for non-existent images, should also be investigated. Additionally, network signatures can be established to detect any unauthorized requests to known endpoints serving screenshots.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2026-21889 lies in its representation of the risks associated with improper access controls in web applications. Organizations must remain vigilant regarding the security of their tools and ensure that all components are regularly updated to mitigate exposure. Additionally, this vulnerability serves as a reminder for security teams to assess their security measures continuously.
For organizations looking to enhance their security posture, it is recommended to engage in red teaming exercises to uncover hidden vulnerabilities and improve response strategies.
Security teams should also consider leveraging penetration testing to validate the effectiveness of their security controls and to ensure that similar vulnerabilities are addressed proactively.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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