CVE-2026-114501

Pillow: Arrow export leaks stale heap memory when PILLOW_ALIGNMENT > 1

MEDIUM
5.3
CVSS Score
Published: October 21, 2026 at 09:17 PM UTC
Updated: October 30, 2026 at 05:17 PM UTC
2 products affected across 2 vendorsPillowPillow

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.4%
SSVC
PoC

Description

Pillow is a Python imaging library. From 11.2.1 until 13.0.0, Arrow export assumes that an image's rows are tightly contiguous and exports from im->blocks[0].ptr even when PILLOW_ALIGNMENT makes aligned_linesize include row padding or an aligned offset before the first row. The resulting Arrow buffer can include uninitialized padding, bytes preceding the first row, or stale heap contents from previously freed images. Applications that configure alignment and export images to Arrow can therefore disclose one user's pixels or other process memory to another user. This issue is fixed in version 13.0.0.

Affected

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

11.2.1 ≤ v < 13.0.0

Remediation

No guide yet

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

References (4)

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

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

CVSS

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

Quick Info

StatusMODIFIED
CWE
CWE-226CWE-908

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