EFence EUVD-2026-66346

Exploitation requires valid credentials to the EFence application at a low-privilege level (CVSS PR:L confirmed). No special non-default configuration or specific deployment mode is described as a prerequisite - any authenticated EFence user on versions 1.2.66 or earlier with access to the upload feature falls within the attack surface. Key limiting factors: authentication is mandatory, which prevents unauthenticated internet-wide scanning; SSVC rates automatable as 'no,' indicating the attack likely requires manual interaction or per-target knowledge rather than fully automated worm-style exploitation; and the product's regional deployment limits the pool of potential targets. Exploitation is limited to the EFence web server's process privilege context, with no subsequent system scope change indicated (SC:N/SI:N/SA:N in CVSS 4.0).

The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H) confirms network accessibility with low attack complexity and no special attack requirements, requiring only low-privilege authentication. SSVC rates technical impact as total, consistent with full server compromise via web shell execution. However, SSVC also rates current exploitation as none and automatable as no, and EPSS stands at just 0.60% (46th percentile), indicating low probability of observed exploitation in the near term - likely due to EFence's limited global deployment footprint and the authentication prerequisite that prevents mass automated scanning. This is a high-severity vulnerability in terms of technical impact if the authentication barrier is cleared, but real-world risk is moderated by the PR:L requirement and the product's regional deployment base. No KEV listing and no public POC further support a current low-urgency exploitation posture, though internal or targeted attackers with valid credentials represent a credible threat.

An attacker who has obtained or guessed valid low-privilege EFence credentials - through credential stuffing, phishing, or insider access - sends a crafted HTTP upload request to EFence's upload endpoint, submitting a web shell script disguised or unrestricted by the application's validation logic. Once uploaded, the attacker directly requests the web shell's URL to execute arbitrary operating system commands with the permissions of the EFence web server process. No public proof-of-concept exploit has been identified at time of analysis, but the attack pattern is well-understood for CWE-434 vulnerabilities.