How severe is CVE-2021-28676?

CVE-2021-28676 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-28676 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-28676?

CVE-2021-28676 primarily affects Python Pillow. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-28676?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-28676 published?

CVE-2021-28676 was published on 2021-06-02 and last updated on 2026-06-17.

CVE-2021-28676

CVE-2021-28676 is a high-severity vulnerability in Python Pillow with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-835.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 2% (82nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-835
Affected product: Python Pillow
Published: 2021-06-02
Last modified: 2026-06-17

Description

An issue was discovered in Pillow before 8.2.0. For FLI data, FliDecode did not properly check that the block advance was non-zero, potentially leading to an infinite loop on load.

Frequently asked questions

What is CVE-2021-28676?: An issue was discovered in Pillow before 8.2.0. For FLI data, FliDecode did not properly check that the block advance was non-zero, potentially leading to an infinite loop on load.
How severe is CVE-2021-28676?: CVE-2021-28676 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-28676 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-28676?: CVE-2021-28676 primarily affects Python Pillow. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-28676?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-28676 published?: CVE-2021-28676 was published on 2021-06-02 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:python:pillow:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*

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