---
id: CVE-2026-79310
title: webpy web.py 0.76 is vulnerable to server-side template injection (SSTI)
summary: >-
  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
  preco…
severity: high
cvss: 8.5
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H'
cwe:
  - CWE-94
published: '2026-09-23'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T21:08:22.573'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-79310'
references:
  - url: 'https://github.com/lichoin/TraceLoom/blob/main/CVEs/CVE-2026-79310.md'
    label: cve@mitre.org
  - url: 'https://github.com/webpy/webpy'
    label: cve@mitre.org
tags:
  - nvd
  - cve.org
epss: 0.00716
epssPercentile: 0.51722
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-09-23T18:21:09.713651Z'
ingestedAt: '2026-09-23T16:27:22.658Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.