CVE-2020-6802

Cross-Site Scripting (XSS) in bleach (CVE-2020-6802)

Summary

Cross-site scripting in bleach (CVE-2020-6802). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 3.1.1 or later.

Original description

The description as published by the source.

In Mozilla Bleach before 3.11, a mutation XSS affects users calling bleach.clean with noscript and a raw tag in the allowed/whitelisted tags option.

Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2020-6802 has been found in bleach.
Risk of unauthorized operations or information disclosure.
What to do: upgrade bleach to 3.1.1 or later.
If unsure, ask your IT team or search "bleach CVE-2020-6802" on the vendor's site.

CVE-2020-6802 (bleach) — CWE-79
Attack vector: remote (network-reachable) / unauthenticated
Patched: 3.1.1 — 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

Cross-site scripting (XSS) (CWE-79) exists in bleach.

📍 Affected scope

Check the vendor advisory for the affected versions of bleach.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 3.1.1.

🛡️ 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 'bleach' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

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

1
Identify exposure identify
```
grep -r 'bleach' . | 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 bleach を grep し、稼働しているサービス・バージョンを把握する。
2
Apply patch patch
```
Upgrade bleach to 3.1.1
```
ステージング環境で 3.1.1 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を含めること。
3
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。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

PyPI bleach

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.1.1"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

Debian DEBIAN-CVE-2020-6802 python-bleach Fixed in: 3.1.1-1

References

Metadata

CVE: CVE-2020-6802
GHSA: GHSA-q65m-pv3f-wr5r
Published: 2020-03-24
First seen on SecPulse: 6 years ago
First-seen source: OSV.dev (Open Source Vulnerabilities)

CWE

CWE-79

Detection sources

OSV.dev (Open Source Vulnerabilities) 2 months ago