What’s Vulnerable › Vulnerabilities

CVE-2021-28678: Insufficient Verification of Data Authenticity in Pillow

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-06-02 · updated 2026-06-17
• Weakness: CWE-345

Description

An issue was discovered in Pillow before 8.2.0. For BLP data, BlpImagePlugin did not properly check that reads (after jumping to file offsets) returned data. This could lead to a DoS where the decoder could be run a large number of times on empty data.

Affected products

• Fedoraproject Fedora: 33
• python-pillow Pillow: before 8.2.0 — fixed in 8.2.0
• Pypi Pillow: before 8.2.0; 1.0, 1.1, 1.2, 1.3, 1.4, 1.5 (+73) — fixed in 8.2.0

How to fix

Upgrade to a fixed version: python-pillow Pillow 8.2.0; Pypi Pillow 8.2.0. Check the vendor advisory for mitigations.

References

• https://github.com/python-pillow/Pillow/pull/5377
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MQHA5HAIBOYI3R6HDWCLAGFTIQP767FL/
• https://pillow.readthedocs.io/en/stable/releasenotes/8.2.0.html#cve-2021-28678-fix-blp-dos
• https://security.gentoo.org/glsa/202107-33
• https://github.com/python-pillow/Pillow/pull/5377
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MQHA5HAIBOYI3R6HDWCLAGFTIQP767FL/
• https://pillow.readthedocs.io/en/stable/releasenotes/8.2.0.html#cve-2021-28678-fix-blp-dos
• https://security.gentoo.org/glsa/202107-33

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