CVE-2023-51643: RCE in Allegra Upload File Function

Successful exploitation of CVE-2023-51643 allows an attacker to execute arbitrary code on the Allegra server with LOCAL SERVICE privileges. This could lead to complete system compromise, including data exfiltration, malware installation, and denial of service. The ability to bypass authentication significantly broadens the attack surface, as it removes a key barrier to entry. The LOCAL SERVICE context, while not the most privileged, still grants considerable access to system resources and data, potentially allowing for lateral movement within the network if the Allegra server has access to other sensitive systems. This vulnerability shares similarities with other directory traversal exploits where attackers manipulate file paths to access unauthorized resources.

1. Reserved2023-12-20
2. Published2024-11-22
3. Modified2024-11-25
4. EPSS updated2026-04-02

The primary mitigation for CVE-2023-51643 is to immediately upgrade Allegra to version 7.5.1 or later. If upgrading is not immediately feasible, consider implementing temporary workarounds such as restricting file upload locations to a tightly controlled directory and implementing strict input validation on all user-supplied file paths. Review and strengthen authentication mechanisms to ensure they are robust and resistant to bypass attempts. Monitor Allegra server logs for suspicious file upload activity, particularly attempts to access or create files outside of the designated upload directory. While a specific WAF rule isn't readily available, generic rules to block directory traversal attempts (e.g., blocking sequences like '../') can provide some protection.