dbcve.org
PillowApplication · Python

CVE-2026-42308

MEDIUM · 5.5 CVSS v3.1 Published 2026-05-09
Fix available
A fix is available. Upgrade to 12.2.0 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Pillow is a Python imaging library. Prior to version 12.2.0, if a font advances for each glyph by an exceeding large amount, when Pillow keeps track of the current position, it may lead to an integer overflow. This issue has been patched in version 12.2.0.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

In Pillow versions prior to 12.2.0, the font rendering code tracks cursor position for each glyph. When a font specifies an extremely large advance value for a glyph, the position tracking variable can overflow due to integer overflow, potentially causing unexpected behavior in image rendering.

MitigationUpgrade Pillow to version 12.2.0 or later to receive the patch for this integer overflow vulnerability.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
PillowApplication
Affected:< 12.2.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed Pillow version
    Run 'python -c "import PIL; print(PIL.__version__)"' or 'pip show pillow' to retrieve the installed version number
    Affected if The version is lower than 12.2.0 (e.g., 12.1.0, 12.0.0, 11.x.x, etc.)
  2. Verify font rendering is in use
    Inspect application code for imports and usage of PIL.ImageFont, PIL.ImageDraw, or related modules that render text using ImageDraw.text() or ImageDraw.multiline_text()
    Affected if The application uses Pillow's ImageFont or ImageDraw text rendering functions with custom or loaded fonts
  3. Identify custom font loading
    Search code for ImageFont.truetype() or ImageFont.load() calls loading .ttf or .otf files, especially from untrusted or third-party sources
    Affected if Custom fonts are loaded via ImageFont.truetype() - these fonts may contain glyph advance values that could trigger the overflow
  4. Check for large font metric values
    If custom fonts are used, examine the font files with a font tool to check for unusually large horizontal advance values on glyphs, or monitor for rendering anomalies when using such fonts
    Affected if Fonts with excessively large glyph advance values are loaded and rendered, causing the position counter to overflow during text layout

A user is affected if Pillow version is below 12.2.0 AND the application renders text using ImageFont with potentially malicious or large custom fonts that could cause integer overflow in glyph position tracking.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 12.2.0 or later
Fixed in 12.2.0
Interim mitigation

Upgrade Pillow to version 12.2.0 or later to receive the patch for this integer overflow vulnerability.

Recommended fix High confidence

12.2.0

  1. 1. Backup your current project and test environment
  2. 2. Run 'pip install Pillow==12.2.0' to upgrade to the patched version
  3. 3. Verify the installation by running 'pip show Pillow' and confirming version 12.2.0
  4. 4. Run your application's test suite to verify functionality after the upgrade
  5. 5. If using requirements files, update the Pillow version constraint to 'Pillow>=12.2.0'
Caveat Review Pillow 12.2.0 release notes for any minor behavior changes; patch releases typically have low risk

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Pillow Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
5.0 hours of engineering $860
Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-42308 in production — separate from our analysis above.

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What belongs here
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  • Version or environment caveats, and links to real fixes
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