# CVE-2026-123534: Tornado before 6.6 Path Traversal via static_url() Version Hashing

Status: published. Published: 2026-11-08. Updated: 2026-11-09.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- tornadoweb / tornado (tornado): ≥ 0; < 6.6 (affected, custom); 6.6 (unaffected, custom). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 8.3 (high); CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 6.5 (medium); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H; source: CNA: VulnCheck

- CVSS 4.0: 8.3 (high); CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 6.5 (medium); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: 0.34% as of 2026-11-09; percentile 27.37%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-22

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/tornadoweb/tornado/security/advisories/GHSA-v8g8-cp5j-42fg (CNA: VulnCheck; vendor-advisory)

- https://www.vulncheck.com/advisories/tornado-before-6.6-path-traversal-via-static-url-version-hashing (CNA: VulnCheck; third-party-advisory)

- https://github.com/tornadoweb/tornado/security/advisories/GHSA-v8g8-cp5j-42fg (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/tornado-before-6.6-path-traversal-via-static-url-version-hashing (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-123534; retrieved 2026-11-09; source updated 2026-11-09

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123534; retrieved 2026-11-08; source updated 2026-11-08

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-123534; retrieved 2026-11-09; source updated Not reported

Revision: a9b0d73a3a4cf63196e692ad5aa37f1fe7f724f3edb22f2075f35276be483c27

Canonical: https://y2.dev/cve/CVE-2026-123534

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- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.