Heap out-of-bounds write via rank-filter size overflow
Published Jul 14, 2026 · Updated Jul 14, 2026
Heap out-of-bounds write in Pillow before 12.3.0 allows remote attackers to corrupt process memory via a large odd rank-filter size. ImageFilter.RankFilter.filter() expands the image before validating the size, while ImagingExpand() uses unchecked signed integer arithmetic and writes beyond the wrapped allocation. Reachability requires an application to let untrusted input control the filter size; supplied image pixels can influence sequential one- or four-byte writes.
Summary
What happened
Heap out-of-bounds write in Pillow before 12.3.0 allows remote attackers to corrupt process memory via a large odd rank-filter size. ImageFilter.RankFilter.filter() expands the image before validating the size, while ImagingExpand() uses unchecked signed integer arithmetic and writes beyond the wrapped allocation. Reachability requires an application to let untrusted input control the filter size; supplied image pixels can influence sequential one- or four-byte writes.
The record
- CVE
- CVE-2026-59197
- Published
- Jul 14, 2026
- Updated
- Jul 14, 2026
- Vendor
- Pillow
- Product
- Pillow
- Classifications
- CWE-190, CWE-787
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 14, 2026CVE publishedPublication date reported by the CVE source.
- Jul 14, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=< 12.3.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
- Upstream minimal ASAN crash proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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