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Pillow vulnerability can cause write buffer overflow on BCn encoding

High severity GitHub Reviewed Published Jul 1, 2025 in python-pillow/Pillow • Updated Jul 2, 2025

Package

pip pillow (pip)

Affected versions

>= 11.2.0, < 11.3.0

Patched versions

11.3.0

Description

There is a heap buffer overflow when writing a sufficiently large (>64k encoded with default settings) image in the DDS format due to writing into a buffer without checking for available space.

This only affects users who save untrusted data as a compressed DDS image.

  • Unclear how large the potential write could be. It is likely limited by process segfault, so it's not necessarily deterministic. It may be practically unbounded.
  • Unclear if there's a restriction on the bytes that could be emitted. It's likely that the only restriction is that the bytes would be emitted in chunks of 8 or 16.

This was introduced in Pillow 11.2.0 when the feature was added.

References

@radarhere radarhere published to python-pillow/Pillow Jul 1, 2025
Published to the GitHub Advisory Database Jul 1, 2025
Reviewed Jul 1, 2025
Published by the National Vulnerability Database Jul 1, 2025
Last updated Jul 2, 2025

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(1st percentile)

Weaknesses

CVE ID

CVE-2025-48379

GHSA ID

GHSA-xg8h-j46f-w952

Source code

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