CVE-2026-112898: python-pillow pillow Use of Uninitialized Variable
Vulnerability summary
CVE-2026-112898 is a medium (CVSS 6.9) Use of Uninitialized Variable vulnerability in python-pillow pillow. EPSS estimates a 0.29% chance of exploitation in the next 30 days, higher than 20.4% of scored vulnerabilities.
Timeline
- 19-10-2026PublishedVulnerability first disclosed.
Description
Pillow is a Python imaging library. From 9.1.0 until 13.0.0, Pillow can disclose uninitialized stack memory when Image.quantize() uses an empty palette. ImagingPaletteCacheUpdate() leaves a local cache array uninitialized when the palette has zero entries, and the conversion path emits those bytes as output pixel indices. An attacker who controls the palette image can obtain stack contents from a returned PNG or GIF. This can disclose addresses and stack-canary data without an out-of-bounds access, memory corruption, or process crash. This issue is fixed in version 13.0.0.
CVSS metrics
2 scores · 2 sources · 1 version- NVDNIST6.9MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS trend
Probability
0.29%
Chance of exploitation in the next 30 days
Percentile
20%
Versus all other CVEs
30-day change
Change unavailable
Change unavailable
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Debian1 product
- pillowAll versions (No fix recorded)
Python-pillow1 product
- pillow≥ 9.1.0, < 13.0.0
2 vendors · 2 products
References
4 links- github.com/python-pillow/Pillow/security/advisories/GHSA-rfgq-q3w2-pmv2X Refsource CONFIRM
- github.com/python-pillow/Pillow/releases/tag/13.0.0X Refsource MISC