CVE-2026-79310
HighCVSS 8.5Exploitation Probability (EPSS)
Elevated risk52th percentile - higher than 52% of all known CVEs
Summary
webpy web.py 0.76 is vulnerable to server-side template injection (SSTI). When an application precompiles templates from a directory the attacker can write to and later renders them through the precompiled template loader, the sandbox is bypassed, allowing arbitrary Python code execution and OS command execution on the server.
Risk Assessment
An attacker can remotely execute arbitrary code in the application context, leading to full server compromise, data leakage, and loss of confidentiality and integrity.
Recommendation
Update web.py to a non-vulnerable version, restrict write permissions on template directories, and avoid using precompiled templates from user-writable locations.
Other vulnerabilities in web.py
See all- CVE-2026-79313Critical
webpy web.py 0.76 is vulnerable to Insufficient Session Expiration. The application's session management relies on periodic cleanup to expire sessions instead of checking the last-access time when a session is loaded. As a result, an expired session whose record has not yet been cleaned up can still be replayed and used, allowing an attacker holding a previously valid session cookie to continue accessing protected resources after the configured idle timeout.
- CVE-2026-79312Medium
webpy web.py 0.76 is vulnerable to Session Fixation. The Session._load() component reads session_id directly from the request cookie and loads that session from the store, and _save() writes back under the same session_id; there is no rotation after authentication, so a fixed session_id keeps the authenticated state.
- CVE-2026-79311Low risk· EPSS 9%
webpy web.py 0.76 is vulnerable to Cross Site Scripting (XSS) via render_jinja.__init__().
Original NVD description (English source)
webpy web.py 0.76 is vulnerable to server-side template injection (SSTI). The template engine can be tricked into executing attacker-controlled template code that built-in security checks are designed to reject. When an application precompiles templates from a directory the attacker can write to and later renders them through the precompiled template loader, the sandbox is bypassed and the attacker's code runs, resulting in arbitrary Python code execution and OS command execution on the server.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS