How severe is CVE-2026-55379?

CVE-2026-55379 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-2026-55379 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-55379?

CVE-2026-55379 affects Python Pillow. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-55379?

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-2026-55379 published?

CVE-2026-55379 was published on 2026-07-06 and last updated on 2026-07-07.

CVE-2026-55379

CVE-2026-55379 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-789.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 0% (29th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-789
Affected product: Python Pillow
Published: 2026-07-06
Last modified: 2026-07-07

Description

Pillow is a Python imaging library. Prior to 12.3.0, PIL/BdfFontFile.py bdf_char() read the BBX width and height field from a BDF font file and passed attacker-controlled dimensions to Image.new() without calling Image._decompression_bomb_check(), bypassing Pillow's documented decompression bomb protection and allowing excessive memory allocation. This issue is fixed in version 12.3.0.

Frequently asked questions

What is CVE-2026-55379?: Pillow is a Python imaging library. Prior to 12.3.0, PIL/BdfFontFile.py bdf_char() read the BBX width and height field from a BDF font file and passed attacker-controlled dimensions to Image.new() without calling Image._decompression_bomb_check(), bypassing Pillow's documented decompression bomb protection and allowing excessive memory allocation. This issue is fixed in version 12.3.0.
How severe is CVE-2026-55379?: CVE-2026-55379 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-2026-55379 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-55379?: CVE-2026-55379 affects Python Pillow. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-55379?: 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-2026-55379 published?: CVE-2026-55379 was published on 2026-07-06 and last updated on 2026-07-07.

References

Affected products (1)

cpe:2.3:a:python:pillow:*:*:*:*:*:*:*:*

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