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High

Pillow: Out-of-bounds access in _imagingmorph on a zero-width image

  • Disclosed: 20.10.2026
  • Updated: 20.10.2026 23:29

Summary

A PPM or PGM file can declare a width of 0, which Pillow accepts, producing an image of size (0, N). Passing that image to ImageMorph.MorphOp.apply() makes the native morphology code index a row buffer at outrow[width - 1], which is outrow[-1] when the width is 0. The process crashes.

Details

The PPM parser reads width and height with no lower-bound check:

  • src/PIL/PpmImagePlugin.py:119

The native apply() writes the row edges with no guard that the width is positive:

  • src/_imagingmorph.c:81 sets outrow[0] = outrow[width - 1] = 0;

match() and get_on_pixels() use the same edge-indexing pattern.

PoC

python
from PIL import Image, ImageMorph

# A width-0 image (also producible from a crafted PPM header). apply() indexes
# outrow[width - 1] == outrow[-1] in native code.
im = Image.new("L", (0, 5))
ImageMorph.MorphOp(op_name="dilation4").apply(im)

Run it:

bash
$ python 03_poc.py
Segmentation fault (core dumped)

Observed on a source build of commit 3e2ab96.

Under AddressSanitizer:

==ERROR: AddressSanitizer: SEGV on unknown address (pc ... in apply)
    #0 apply   src/_imagingmorph.c:81
SUMMARY: AddressSanitizer: SEGV src/_imagingmorph.c:81 in apply

With width 0 the outrow[width - 1] write lands on an unmapped page, so it surfaces as a SEGV pinned to the edge-write line rather than a redzone overflow.

Impact

Out-of-bounds write in a C extension. Affects any application that runs a morphology operation on an image opened from untrusted input. Result is a crash and possible memory corruption.

What to do

Upgrade pillow to version 13.0.0 or later.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Python (PyPI) pillow < 13.0.0 13.0.0

References

CVSS score -
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Weakness (CWE)
CWE-787
Platform
Python (PyPI)
Package
pillow
Disclosed
20.10.2026
Updated
20.10.2026 23:29

Sources and licenses · Edited or translated by DockRay; source rights and applicable licenses are retained.

OSV / GitHub Advisory Database - GHSA-58r4-6rv3-gfh8 - CC BY 4.0

Vulnerability history: pillow

All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (81) in the archive
Total entries
81
First → latest
04.2014 10.2026
Without a fix
0
Exploited in attacks
1

Severity breakdown

  • Critical 10
  • High 53
  • Medium 16
  • Low 1
  • Unrated 1

Disclosures per year

earlier: 12

Severity:
  1. Pillow: Out-of-bounds access in _imagingmorph on a zero-width image this entry
    High CVE-2026-112397 < 13.0.0 13.0.0
  2. Pillow: GIF seek keeps rejected size after DecompressionBombError, allowing DoS
    High CVE-2026-112400 >= 9.2.0, < 13.0.0 13.0.0
  3. Pillow: Unbounded recursion parsing a PDF page tree or trailer chain (incomplete fix for CVE-2026-42310)
    High CVE-2026-112895 >= 5.1.0, < 13.0.0 13.0.0
  4. Pillow JPEG2000 tiled decode retains a growing scratch buffer and can be used for denial of service
    High CVE-2026-59204 >= 8.2.0, < 12.3.0 12.3.0
  5. Pillow: Decompression Bomb DoS via PdfParser.PdfStream.decode()
    High · 7.5 CVE-2026-59200 >= 5.1.0, < 12.3.0 12.3.0
  6. Pillow: Out-of-bounds read via attacker-controlled row stride on Pillow's mmap path (McIdas AREA files)
    High CVE-2026-54058 < 12.3.0 12.3.0
  7. Pillow: Heap out-of-bounds write in `ImageFilter.RankFilter` via integer overflow in `ImagingExpand`
    High · 8.2 CVE-2026-59197 < 12.3.0 12.3.0
  8. Pillow: Controlled heap out-of-bounds write in Pillow `ImageCmsTransform.apply()` via output mode mismatch
    High · 7.5 CVE-2026-59205 < 12.3.0 12.3.0
  9. Pillow: Heap out-of-bounds write `Image.paste()` / `Image.crop()` via signed coordinate overflow
    High · 7.5 CVE-2026-59199 < 12.3.0 12.3.0
  10. Pillow: `FontFile.compile()`: `Image.new()` called without `_decompression_bomb_check()`
    High · 7.5 CVE-2026-54060 < 12.3.0 12.3.0
  11. Pillow `PcfFontFile._load_bitmaps()`: `Image.frombytes()` called without `_decompression_bomb_check()` — bomb protection bypass via PCF font loading
    High · 7.5 CVE-2026-54059 < 12.3.0 12.3.0
  12. Pillow `BdfFontFile`: `Image.new()` called without `_decompression_bomb_check()` — bomb protection bypass via font loading
    High · 7.5 CVE-2026-55379 < 12.3.0 12.3.0
  13. Pillow `GdImageFile._open()`: image dimensions accepted without `_decompression_bomb_check()`
    High · 7.5 CVE-2026-55380 < 12.3.0 12.3.0
  14. Pillow has an OOB Write with Invalid PSD Tile Extents (Integer Overflow)
    High CVE-2026-42311 >= 10.3.0, < 12.2.0 12.2.0
  15. FITS GZIP decompression bomb in Pillow
    High · 7.5 CVE-2026-40192 >= 10.3.0, < 12.2.0 12.2.0
  16. Pillow affected by out-of-bounds write when loading PSD images
    High CVE-2026-25990 >= 10.3.0, < 12.1.1 12.1.1
  17. Pillow vulnerability can cause write buffer overflow on BCn encoding
    High · 7.1 CVE-2025-48379 >= 11.2.0, < 11.3.0 11.3.0
  18. Pillow buffer overflow vulnerability
    High · 6.7 CVE-2024-28219 < 10.3.0 10.3.0
  19. Arbitrary Code Execution in Pillow
    Critical · 8.1 CVE-2023-50447 < 10.2.0 10.2.0
  20. An issue was discovered in Pillow before 10.0.0. It is a Denial of Service that uncontrollably allocates memory to process a given task, potentially causing a service to crash by having it run out of
    High · 7.5 CVE-2023-44271 < 10.0.0 10.0.0
  21. libwebp: OOB write in BuildHuffmanTable
    High · 8.8 Exploited in attacks CVE-2023-4863 < 10.0.1 10.0.1
  22. Pillow before 9.3.0 allows denial of service via SAMPLESPERPIXEL.
    High · 7.5 CVE-2022-45199 >= 9.2.0, < 9.3.0 9.3.0
  23. Pillow before 9.2.0 performs Improper Handling of Highly Compressed GIF Data (Data Amplification).
    High · 7.5 CVE-2022-45198 < 9.2.0 9.2.0
  24. Buffer over-flow in Pillow
    High · 7.5 CVE-2022-30595 >= 9.1.0, < 9.1.1 9.1.1
  25. Path traversal in Pillow
    High · 9.1 CVE-2022-24303 < 9.0.1 9.0.1
  26. Arbitrary expression injection in Pillow
    Critical · 9.8 CVE-2022-22817 < 9.0.1 9.0.1
  27. Uncontrolled Resource Consumption in pillow
    High · 7.5 CVE-2021-23437 >= 5.2.0, < 8.3.2 8.3.2
  28. Buffer Overflow in Pillow
    Critical · 9.8 CVE-2021-34552 < 8.3.0 8.3.0
  29. Uncontrolled Resource Consumption in Pillow
    High · 7.5 CVE-2021-28677 < 8.2.0 8.2.0
  30. Potential infinite loop in Pillow
    High · 7.5 CVE-2021-28676 < 8.2.0 8.2.0
  31. Pillow Out-of-bounds Read vulnerability
    High · 9.1 CVE-2021-25288 >= 2.4.0, < 8.2.0 8.2.0
  32. Out-of-bounds Read in Pillow
    High · 9.1 CVE-2021-25287 >= 2.4.0, < 8.2.0 8.2.0
  33. Pillow denial of service
    High · 5.5 CVE-2021-28675 < 8.2.0 8.2.0
  34. Out of bounds read in Pillow
    High · 7.5 CVE-2021-25293 >= 4.3.0, < 8.1.1 8.1.1
  35. Out of bounds read in Pillow
    High · 7.5 CVE-2021-25291 < 8.2.0 8.2.0
  36. Out-of-bounds Write in Pillow
    High · 7.5 CVE-2021-25290 < 8.1.1 8.1.1
  37. Out of bounds write in Pillow
    Critical · 9.8 CVE-2021-25289 < 8.1.1 8.1.1
  38. Pillow Denial of Service by Uncontrolled Resource Consumption
    High · 7.5 CVE-2021-27923 < 8.1.2 8.1.2
  39. Pillow Uncontrolled Resource Consumption
    High · 7.5 CVE-2021-27922 < 8.1.2 8.1.2
  40. Pillow Denial of Service by Uncontrolled Resource Consumption
    High · 7.5 CVE-2021-27921 < 8.1.2 8.1.2
Show more (20) Showing 40 of 63

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