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Medium

Pillow has a PDF Parsing Trailer Infinite Loop (DoS)

  • Disclosed: 04.05.2026
  • Updated: 11.10.2026 15:17

Impact

An attacker can supply a malicious PDF that causes the process to hang indefinitely, consuming 100% CPU and making the application unresponsive.

Patches

Patched version: 12.2.0.

PdfParser (introduced in Pillow 4.2.0) follows Prev pointers in PDF trailers to read cross-reference sections. If a trailer's Prev pointer references an offset that has already been processed — either pointing to itself or forming a longer cycle — the parser enters an infinite loop. Pillow now tracks previously processed trailer offsets and raises an error if a cycle is detected.

Workarounds

Use any version but the affected versions: >= 4.2.0, < 12.2.0

Resources

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Python (PyPI) pillow >= 4.2.0, < 12.2.0 12.2.0

References

CVSS score 5.5/10
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE)
CWE-835
Platform
Python (PyPI)
Package
pillow
Disclosed
04.05.2026
Updated
11.10.2026 15:17

Sources and licenses

OSV / GitHub Advisory Database - PYSEC-2026-2874 - PyPA Advisory Database; CC BY 4.0

OSV / GitHub Advisory Database - GHSA-r73j-pqj5-w3x7 - 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
    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. Pillow has a PDF Parsing Trailer Infinite Loop (DoS) this entry
    Medium · 5.5 CVE-2026-42310 >= 4.2.0, < 12.2.0 12.2.0
  16. FITS GZIP decompression bomb in Pillow
    High · 7.5 CVE-2026-40192 >= 10.3.0, < 12.2.0 12.2.0
  17. Pillow affected by out-of-bounds write when loading PSD images
    High CVE-2026-25990 >= 10.3.0, < 12.1.1 12.1.1
  18. 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
  19. Pillow buffer overflow vulnerability
    High · 6.7 CVE-2024-28219 < 10.3.0 10.3.0
  20. Arbitrary Code Execution in Pillow
    Critical · 8.1 CVE-2023-50447 < 10.2.0 10.2.0
Show more (20) Showing 20 of 64

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