CVE-2026-42309

Process crash via recursively unpacked coordinate lists

Published May 9, 2026 · Updated May 9, 2026

Heap buffer overflow in Pillow 11.2.1 through 12.1.1 allows local users to crash a consuming process via nested coordinate lists. ImagePath.Path, ImageDraw.ImageDraw.polygon, and ImageDraw.ImageDraw.line recursively flatten nested elements beyond the allocated coordinate buffer instead of requiring numeric pairs. Exploitation requires control of coordinates passed to an affected API; published assessments bound the demonstrated consequence to process availability.

CVSS severity5.1
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap buffer overflow in Pillow 11.2.1 through 12.1.1 allows local users to crash a consuming process via nested coordinate lists. ImagePath.Path, ImageDraw.ImageDraw.polygon, and ImageDraw.ImageDraw.line recursively flatten nested elements beyond the allocated coordinate buffer instead of requiring numeric pairs. Exploitation requires control of coordinates passed to an affected API; published assessments bound the demonstrated consequence to process availability.

The record

CVE
CVE-2026-42309
Published
May 9, 2026
Updated
May 9, 2026
Vendor
Pillow
Product
Pillow
Classifications
CWE-122, T1499
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 9, 2026CVE publishedPublication date reported by the CVE source.
  2. May 9, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 11.2.1, < 12.2.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Pillow · Pillowversion=>= 11.2.1, < 12.2.0

Published CVSS scores

5.1GitHub, Inc.CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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