Medium 6.3Published Oct 21, 2026

CVE-2026-114501Pillow: Arrow export leaks stale heap memory when PILLOW_ALIGNMENT > 1

Updated under an hour ago (2026-10-22 10:50 UTC)

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No exploitation reported and no EPSS estimate yet.

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Every CVE for python-pillow Pillow

Exploited in the last 30 days

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.

CVSS: 6.3 MEDIUM (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
Weakness (CWE): CWE-226, CWE-908
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Received
Record last updated: Oct 21, 2026
First seen by InfoSec Signals: Oct 21, 2026

Affected products

Affected products

python-pillow Pillow python_pillow:pillow (from the name)	from 11.2.1, < 13.0.0	CNA record

References

https://github.com/python-pillow/Pillow/security/advisories/GHSA-654x-cwwv-5j9cx-refsource-confirm
https://github.com/python-pillow/Pillow/pull/10172x-refsource-misc
https://github.com/python-pillow/Pillow/commit/19f64946eb247b973dd4560be7dea3bf979d2e6ax-refsource-misc
https://github.com/python-pillow/Pillow/releases/tag/13.0.0x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.