The bluemonday sanitizer before 1.0.16 for Go, and before 0.0.8 for Python (in…
Priority MEDIUM 45CWE-20Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub.
Summary
The bluemonday sanitizer before 1.0.16 for Go, and before 0.0.8 for Python (in pybluemonday), does not properly enforce policies associated with the SELECT, STYLE, and OPTION elements.
Why it matters now
EPSS 0.01564 75th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed pybluemonday (PyPI): 0.0.8github.com/microcosm-cc/bluemonday (Go): 1.0.16
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
| — | pybluemonday (PyPI) | before 0.0.8 | 0.0.8 | Patch available | GHSA-x95h-979x-cf3j |
| — | github.com/microcosm-cc/bluemonday (Go) | before 1.0.16 | 1.0.16 | Patch available | GHSA-x95h-979x-cf3j |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
- pybluemonday (PyPI) Vendor— Affected before 0.0.8 Fixed in 0.0.8 Patch available GHSA-x95h-979x-cf3j
- github.com/microcosm-cc/bluemonday (Go) Vendor— Affected before 1.0.16 Fixed in 1.0.16 Patch available GHSA-x95h-979x-cf3j
CPE configurations NVD · 2
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:microco:bluemonday:*:*:*:*:*:go:*:* | before 1.0.16 | Vulnerable | Microco |
| cpe:2.3:a:python:pybluemonday:*:*:*:*:*:*:*:* | before 0.0.8 | Vulnerable | python-pillow |
- cpe:2.3:a:microco:bluemonday:*:*:*:*:*:go:*:* Versions before 1.0.16 Vulnerable ·Microco
- cpe:2.3:a:python:pybluemonday:*:*:*:*:*:*:*:* Versions before 0.0.8 Vulnerable ·python-pillow
Remediation
- Fix · GHSA-x95h-979x-cf3j pybluemonday (PyPI) Fixed in 0.0.8 Advisory →
- Fix · GHSA-x95h-979x-cf3j github.com/microcosm-cc/bluemonday (Go) Fixed in 1.0.16 Advisory →
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2021-42576
- 2026-10-03 Alias added: GHSA-x95h-979x-cf3j
References
Advisory 2
Other 6
- https://github.com/microcosm-cc/bluemonday/commit/c788a2a4d42e081ad54a31368478820bb4a42fb4
- https://docs.google.com/document/d/11SoX296sMS0XoQiQbpxc5pNxSdbJKDJkm5BDv0zrX50
- https://github.com/microcosm-cc/bluemonday
- https://github.com/pypa/advisory-database/tree/main/vulns/pybluemonday/PYSEC-2021-849.yaml
- https://pkg.go.dev/vuln/GO-2022-0588
- https://pypi.org/project/pybluemonday
Sources
- CVE-2021-42576 · CVE Program
- CVE-2021-42576 · NVD
- FIRST EPSS
- GHSA-x95h-979x-cf3j · GitHub Advisory Database · CC BY 4.0
- CVE-2021-42576 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences