Regular expression denial of service (ReDoS) in Pillow
Priority LOW 39CWE-125Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 1 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-125 and the CVSS impact.
Summary
The package pillow 5.2.0 and before 8.3.2 are vulnerable to Regular Expression Denial of Service (ReDoS) via the getrgb function.
Why it matters now
EPSS 0.0324 88th percentileScored 2026-11-07
Fix Partial Pillow: 8.3.2pillow (PyPI): 8.3.2Red Hat: 1 without a fix
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 |
|---|---|---|---|---|---|
| — | Pillow | all versions; before 8.3.2 | 8.3.2 | Patch available | CNA |
| — | pillow (PyPI) | 5.2.0 to before 8.3.2 | 8.3.2 | Patch available | GHSA-98vv-pw6r-q6q4 |
- Pillow Vendor— Affected all versions; before 8.3.2 Fixed in 8.3.2 Patch available CNA
- pillow (PyPI) Vendor— Affected 5.2.0 to before 8.3.2 Fixed in 8.3.2 Patch available GHSA-98vv-pw6r-q6q4
CPE configurations NVD · 3
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:python:pillow:*:*:*:*:*:*:*:* | 5.2.0 to before 8.3.2 | Vulnerable | python-pillow |
| cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* | 33 | Vulnerable | Fedoraproject |
| cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* | 34 | Vulnerable | Fedoraproject |
- cpe:2.3:a:python:pillow:*:*:*:*:*:*:*:* Versions 5.2.0 to before 8.3.2 Vulnerable ·python-pillow
- cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* Versions 33 Vulnerable ·Fedoraproject
- cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* Versions 34 Vulnerable ·Fedoraproject
Remediation
- Fix · CNA Pillow Fixed in 8.3.2
- Fix · GHSA-98vv-pw6r-q6q4 pillow (PyPI) Fixed in 8.3.2 Advisory →
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Quay 3 | Affected | No fix yet |
Not affected: 2 products
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
Timeline
- 2026-10-02 Threatist record created from CVE-2021-23437
- 2026-10-03 Alias added: GHSA-98vv-pw6r-q6q4
References
Advisory 6
Other 7
- [debian-lts-announce] 20240322 [SECURITY] [DLA 3768-1] pillow security update
- https://github.com/pypa/advisory-database/tree/main/vulns/pillow/PYSEC-2021-317.yaml
- https://github.com/python-pillow/Pillow
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RNSG6VFXTAROGF7ACYLMAZNQV4EJ6I2C
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VKRCL7KKAKOXCVD7M6WC5OKFGL4L3SJT
- https://lists.fedoraproject.org/archives/list/[email protected]/message/RNSG6VFXTAROGF7ACYLMAZNQV4EJ6I2C
- https://lists.fedoraproject.org/archives/list/[email protected]/message/VKRCL7KKAKOXCVD7M6WC5OKFGL4L3SJT
Sources
- CVE-2021-23437 · CVE Program
- CVE-2021-23437 · NVD
- FIRST EPSS
- GHSA-98vv-pw6r-q6q4 · GitHub Advisory Database · CC BY 4.0
- CVE-2021-23437 · 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