CVE-2026-1810 is a path traversal vulnerability identified in the bolo-blog project's bolo-solo software, specifically affecting versions 2.6.0 through 2.6.4. The vulnerability resides in the unpackFilteredZip function located in src/main/java/org/b3log/solo/bolo/prop/BackupService.java, which handles ZIP file processing. By manipulating the File argument passed to this function, an attacker can perform path traversal attacks, enabling them to write files outside the intended extraction directory. This can lead to overwriting critical files or placing malicious files in sensitive locations on the server. The vulnerability is remotely exploitable without requiring user interaction or elevated privileges, increasing its risk profile. The CVSS 4.0 score is 5.3 (medium severity), reflecting the moderate impact on confidentiality, integrity, and availability, with low attack complexity and no authentication needed. Despite early disclosure to the bolo-blog project, no official patch or fix has been released, and a public exploit is available, increasing the likelihood of exploitation. The vulnerability primarily affects the ZIP File Handler component, which is critical for backup and content management operations within bolo-solo. Organizations using this software for blogging or content management should consider the risk of unauthorized file writes and potential system compromise.

For European organizations, exploitation of CVE-2026-1810 could lead to unauthorized file writes on servers running vulnerable versions of bolo-solo, potentially resulting in data breaches, defacement of websites, or further system compromise through planted malicious files. This could disrupt business operations, damage reputation, and lead to regulatory non-compliance, especially under GDPR if personal data is exposed or altered. Since bolo-solo is a blogging platform, organizations relying on it for public-facing content or internal communications may face service integrity and availability issues. The medium severity score indicates moderate risk, but the availability of a public exploit and lack of patch heighten the urgency. Attackers could leverage this vulnerability to gain footholds in networks, pivot to other systems, or conduct targeted attacks against European entities. The impact is more pronounced for organizations with limited security monitoring or those exposing the vulnerable service directly to the internet.

1. Immediately restrict network access to the bolo-solo application, limiting it to trusted IP addresses or internal networks to reduce exposure. 2. Implement strict input validation and sanitization on ZIP file uploads, ensuring that file paths do not contain traversal sequences such as '../'. 3. Monitor logs and file system changes for unusual activity related to ZIP file extraction or unexpected file creations outside designated directories. 4. If possible, disable or isolate the backup and ZIP extraction functionality until a patch is available. 5. Engage with the bolo-blog community or maintainers to encourage timely patch development and apply updates as soon as they are released. 6. Consider deploying web application firewalls (WAFs) with custom rules to detect and block path traversal attempts in ZIP file handling. 7. Conduct security awareness training for administrators to recognize signs of exploitation and respond promptly. 8. As a longer-term measure, evaluate alternative blogging or content management platforms with active security support if bolo-solo remains unpatched.