Uncontrolled Memory Allocation in Pillow - CVE-2026-55379
Published: July 3, 2026
Vulnerability identifier: #VU136860
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-55379
CWE-ID: CWE-789
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Alex Clark and Contributors
Affected software:
Pillow
Pillow
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to memory allocation with excessive size value in the PIL/BdfFontFile.py bdf_char() font loading path when parsing a crafted BDF font file with oversized BBX dimensions and an empty BITMAP section. A remote attacker can supply a specially crafted BDF font file to cause a denial of service.
Loaded glyph images persist in memory for the lifetime of the font object.
How to mitigate CVE-2026-55379
Install security update from vendor's website.