CVE-2026-54059

Pillow: PcfFontFile._load_bitmaps()`: `Image.frombytes()` called without `_decompression_bomb_check()` — bomb protection bypass via PCF font loading

HIGH
7.5
CVSS Score
Published: July 6, 2026 at 06:46 PM UTC
Updated: October 25, 2026 at 08:10 PM UTC
2 products affected across 2 vendorsPillowPillow

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Severity
HIGH7.5
Exploit prediction
EPSS 0.4%
SSVC
PoC

Description

Pillow is a Python imaging library. Prior to 12.3.0, PIL/PcfFontFile.py _load_bitmaps() read glyph dimensions from the PCF METRICS section and passed them directly to Image.frombytes() without calling Image._decompression_bomb_check(), allowing crafted PCF font data to cause excessive memory allocation. This issue is fixed in version 12.3.0.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 12.3.0
Affected range stops below 12.3.0, so it looks safe — our inference, not a vendor statement
v < 12.3.0
Affected range stops below 12.3.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-789

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