# CVE-2026-103263: Tornado before 6.5.9 StaticFileHandler Path Traversal via Symlink

> Unauthenticated attackers can read arbitrary files outside the static directory via symlink traversal in Tornado's StaticFileHandler.

- **Severity:** High 8.2 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 Oct 2026
- **Updated:** 1 Oct 2026
- **Also known as:** AZL-105375, BELL-CVE-2026-103263, CLEANSTART-2026-YE37392, DEBIAN-CVE-2026-103263, ECHO-dd3a-7510-fb48, GHSA-4cjq-6jh9-w2f5, GHSA-c2m8-h5v5-343r, MINI-23w9-p73w-wgvh, MINI-36h2-cmq9-m7hc, MINI-377x-37mv-8p9w, MINI-3h78-rm7j-cfwr, MINI-3r36-xr77-6jrv, MINI-4f25-m979-w295, MINI-4vq8-x2cx-68cv, MINI-59j3-vqvw-6rpg, MINI-6gj6-83x4-8f6q, MINI-8qmg-vm4m-7m9m, MINI-c496-v69q-rmrx, MINI-f494-q7hg-jvqm, MINI-fg5v-6723-jcf5, MINI-fp66-4x4c-28ph, MINI-g354-9hj6-q97f, MINI-g4pr-v925-r3jg, MINI-jqff-5j24-cfw3, MINI-jwrm-r9rw-x5r3, MINI-pfh9-24hg-qfwc, MINI-pj2j-2qxw-4j3m, MINI-pvgp-hg38-pxgw, ROOT-APP-PYPI-GHSA-c2m8-h5v5-343r, UBUNTU-CVE-2026-103263

## What is CVE-2026-103263?

CVE-2026-103263 is a high-severity path traversal vulnerability in tornadoweb tornado, published on 1 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Tornado before 6.5.9 contains a path traversal vulnerability in StaticFileHandler that follows symbolic links inside the static root without confirming the resolved target stays within it. When a symlink pointing outside the static directory exists inside it, unauthenticated attackers can request it to read files such as configuration files, private keys, and application secrets accessible to the process user.

Weakness: CWE-59 (Improper Link Resolution Before File Access)

## Which versions are affected by CVE-2026-103263?

2 open source packages ship an affected version, including tornado.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `tornado` | PyPI | All versions | 6.5.9 |
| `tornado` | PyPI | All versions | 6.5.9 |

## How do I fix CVE-2026-103263?

Upgrade tornado to 6.5.9 or later.

## Is CVE-2026-103263 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-103263 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-103263 and fix it if it is affected.

What it is: CVE-2026-103263 is a high-severity path traversal vulnerability in tornadoweb tornado, published on 1 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-103263 exists.

Affected packages and fixed versions:
- tornado (PyPI): affected all versions; fixed in 6.5.9
- tornado (PyPI): affected all versions; fixed in 6.5.9

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-103263/ (Markdown: https://insights.sbomify.com/CVE-2026-103263/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-103263
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-103263
- OSV: https://osv.dev/vulnerability/CVE-2026-103263

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-103263/
Summaries are generated and may contain mistakes; the official description above is the record.