Use After Free in Python-Pillow Pillow
CVE-2026-112396
Pillow is a Python imaging library. From 11.3.0 until 13.0.0, Pillow has a heap use-after-free when libtiff rejects a tag while encoding TIFF data to an in-memory buffer. When an application saves attacker-influenced TIFF tags to BytesIO, libtiff can reject a tag during encoding in ImagingLibTiffEncode; the error path then frees the output buffer without closing or clearing the TIFF handle, and later cleanup flushes through the write callback into freed memory, which can crash the process and may enable code execution. This issue is fixed in version 13.0.0.
Vulnerability class: Use-After-Free
Published .
CVSS v3 metric
CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- Python-Pillow Pillow — versions >= 11.3.0, < 13.0.0
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-112396?
- CVE-2026-112396 is a medium-severity vulnerability in Python-Pillow Pillow, classified under Use After Free. CVSS score: 5.9/10. Published 2026-10-19.
- How severe is CVE-2026-112396?
- Medium severity. CVSS v3 base score is 5.9 out of 10.