---
id: "CVE-2026-123534"
page: "https://infrastack.ai/live/CVE-2026-123534"
kind: "vulnerability"
aliases: ["CVE-2026-123534"]
title: "Tornado: path traversal in static_url() hashes files outside static path"
severity: "high"
cvss: 8.3
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["package", "python", "tornado", "web-apps"]
not_affected_if: ["hard-coded-static-paths", "tornado-6.6-or-later"]
published_at: "2026-11-08T02:16:43+00:00"
first_seen_at: "2026-11-08T02:21:10+00:00"
updated_at: "2026-11-08T02:23:14+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-123534", "first_seen_at": "2026-11-08T02:21:10+00:00"}]
exploit_sources: []
---

# Tornado: path traversal in static_url() hashes files outside static path

Link for people: https://infrastack.ai/live/CVE-2026-123534 (this .md is for agents)

Tornado's RequestHandler.static_url() and get_version() accept ../ sequences, so they hash files outside the static_path directory. An attacker who controls the input can learn whether readable files exist via SHA-512 hashes, or block the event loop by pointing it at /dev/zero.

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

## How to check

- Check the installed Tornado version with `python -c "import tornado; print(tornado.version)"`
- Look for application code that passes user-controlled input into `static_url()`

## Fix

- Tornado: move to `6.6` or later

## Timeline

- 2026-11-08T02:21:10+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-123534

## Documents

- [advisory] Vendor advisory: github.com https://github.com/tornadoweb/tornado/security/advisories/GHSA-v8g8-cp5j-42fg
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/tornado-before-6.6-path-traversal-via-static-url-version-hashing

## From the sources

Tornado before 6.6 contains a path traversal vulnerability in RequestHandler.static_url() and get_version() that allows attackers to hash files outside static_path using ../ sequences. Attackers controlling input passed to static_url() can obtain SHA-512 hashes of readable files to confirm their existence, or reference /dev/zero to block the event loop indefinitely.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_