CVE-2026-59205: Pillow: Controlled heap out-of-bounds write in Pillow `ImageCmsTransform.apply()` via out…

Summary Pillow's public ImageCms.ImageCmsTransform.apply(im, imOut) API can trigger controlled native heap corruption when the caller supplies an output image whose mode does not match the transform's declared output mo…

7.5CVSS Score

HIGHSeverity

NOCISA KEV

0.4%EPSS Score

VulnerabilityImpact Type

📋 Vulnerability Details

CVE ID	CVE-2026-59205
Vendor	pip
Affected Product	pillow
Vulnerability Type	Vulnerability
CVSS Score	7.5 (HIGH)
EPSS Score	0.4% probability of exploitation in the next 30 days
Actively Exploited	❌ No known exploitation
Patch Status	See Vendor Advisory →
Reported By	CYBERDUDEBIVASH SENTINEL APEX Intelligence (via github_advisories)

🔬 Technical Analysis

Summary Pillow's public `ImageCms.ImageCmsTransform.apply(im, imOut)` API can trigger

controlled native heap corruption when the caller supplies an output image whose mode does not match the transform's declared output mode. For example, a transform built as RGBA -> RGBA can be applied to an L output image. Pillow checks dimensions only, then calls LittleCMS with the output row pointer. LittleCMS writes RGBA-sized rows into a 1-byte-per-pixel L image row.

Details `src/PIL/ImageCms.py:ImageCmsTransform.apply()` accepts an optional caller

supplied imOut: ```python def apply(self, im, imOut=None): if imOut is None: imOut = Image.new(self.output_mode, im.size, None) self.transform.apply(im.getim(), imOut.getim()) imOut.info["icc_profile"] = self.output_profile.tobytes() return

🎯 Known Indicators of Compromise

{"type":"domain","value":"imout.info","confidence_score":0.75,"first_seen":"2026-07-20","source_count":1}

📚 Advisory References

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