Vulnerability in python-tornado (UBUNTU-CVE-2026-31958)

Summary

vulnerability in python-tornado (UBUNTU-CVE-2026-31958). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to `6.5.5` or later.

AI summary snake-internal / snake-material-v2

A vulnerability tracked as **UBUNTU-CVE-2026-31958** has been found in python-tornado. Risk of unauthorized operations or information disclosure. CVSS score: ?/10. What to do: upgrade python-tornado to **6.5.5** or later. If unsure, ask your IT team or search "python-tornado UBUNTU-CVE-2026-31958" on the vendor's site.

UBUNTU-CVE-2026-31958 (python-tornado) — Attack vector: remote (network-reachable) / unauthenticated / no user interaction Patched: `6.5.5` — apply immediately Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs. Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

**A vulnerability** (unclassified) exists in python-tornado.

📍 Affected scope

python-tornado — .

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure

🔧 How to fix

Update to **6.5.5**.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run `grep -r 'python-tornado' .` against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response Actions (7 steps)

Concrete steps and command examples for SOC/SRE teams to execute in order

1
Identify exposure identify
```
grep -r 'python-tornado' . | grep -v node_modules
```
リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で `python-tornado` を grep し、稼働しているサービス・バージョンを把握する。
6
Apply patch patch
```
Upgrade python-tornado to 6.5.5
```
ステージング環境で 6.5.5 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスと、Step 3 で見つけた異常検知の続報チェックを含めること。
7
Post-deployment verification verify
```
Confirm patched version is live in production
```
パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 3 と同じログクエリでアラート再発が無いか継続監視。

Affected packages

Ubuntu:Pro:16.04:LTS python-tornado

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.2.1-1ubuntu3.1+esm3"}]}]

Ubuntu:Pro:18.04:LTS python-tornado

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.5.3-1ubuntu0.2+esm3"}]}]

Ubuntu:Pro:20.04:LTS python-tornado

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.0.3+really5.1.1-3ubuntu0.1~esm5"}]}]

Ubuntu:Pro:22.04:LTS python-tornado

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.0-3ubuntu0.1~esm5"}]}]

Ubuntu:24.04:LTS python-tornado

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.4.0-1ubuntu0.5"}]}]

Ubuntu:25.10 python-tornado

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.4.2-3ubuntu0.3"}]}]

Ubuntu:26.04:LTS python-tornado

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.5.4-0.1ubuntu0.1"}]}]

References

advisory https://ubuntu.com/security/notices/USN-8198-1
advisory https://ubuntu.com/security/notices/USN-8198-2
report https://ubuntu.com/security/CVE-2026-31958
report https://www.cve.org/CVERecord?id=CVE-2026-31958
report https://github.com/tornadoweb/tornado/security/advisories/GHSA-qjxf-f2mg-c6mc