---
id: "CVE-2026-120500"
kind: "vulnerability"
aliases: ["CVE-2026-120500"]
title: "Otter Wiki: stored script injection through math code blocks"
severity: "medium"
cvss: 6.1
epss: null
exploited: false
status: "open"
category: "other"
products: []
ecosystems: []
tags: ["other", "otter-wiki", "python", "self-hosted"]
not_affected_if: ["editing-restricted", "version-2.26.2-or-later"]
published_at: "2026-11-02T16:17:34+00:00"
first_seen_at: "2026-11-02T16:24:04+00:00"
updated_at: "2026-11-02T16:26:45+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-120500", "first_seen_at": "2026-11-02T16:24:04+00:00"}]
---

# Otter Wiki: stored script injection through math code blocks

Otter Wiki versions before 2.26.2 render HTML placed inside a math fenced code block without escaping. An attacker who can edit a page, including anonymous users under the default configuration, can store script that runs for every viewer of that page.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed Otter Wiki version against `2.26.2`
- Review whether anonymous editing is enabled on the wiki

## Fix

- Otter Wiki: upgrade to `2.26.2` or later

## Timeline

- 2026-11-02T16:24:04+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-120500

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/an-otter-wiki-before-2.26.2-stored-xss-via-math-code-block
- [fix] Patch: github.com https://github.com/redimp/otterwiki/commit/b2e91d20ed36c01ce140d18698f9abb90685d481
- [fix] Release notes: github.com https://github.com/redimp/otterwiki/releases/tag/v2.26.2

## From the sources

An Otter Wiki before 2.26.2 contains a stored cross-site scripting vulnerability in OtterwikiMdRenderer.block_code that allows attackers who can edit pages, including anonymous users under the default configuration, to inject arbitrary script. Attackers can place HTML inside a math fenced code block, which is rendered unescaped and executes for every viewer of the page.

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