GHSA-gg2r-wvfm-q9rx BIT-pillow-2026-112892 CVE-2026-112892
Pillow: MSP RLE decoder expands a tiny file into unbounded memory
- Severity
- 0.0 / 10
- High · CVSS 4.0
- Exploit chance (EPSS)
- 0.50%
- Chance of exploitation in the next 30 days. Higher than 43.05% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-409 Improper Handling of Highly Compressed Data (Data Amplification)
- Fix
13.0.0- Upgrade pillow to this version or later
Description
Summary
The MSP RLE decoder expands run-length data into an in-memory buffer with no cap tied to the declared image size. A small file that passes the pixel-count check can force hundreds of megabytes or more of allocation when the application loads pixels.
Details
The MSP decoder writes each run into an unbounded io.BytesIO and can expand roughly 85x per run:
src/PIL/MspImagePlugin.py:144-146
Impact
Memory-exhaustion denial of service from a tiny crafted image in any application that loads pixels. The expansion is decoupled from the declared pixel count, so MAX_IMAGE_PIXELS does not bound it.
Affected versions
PyPI
| Package | Vulnerable | Fixed in |
|---|---|---|
| pillow | >= 4.1.0, < 13.0.0 |
13.0.0 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
pillow PyPI → 13.0.0
- pip
pip install --upgrade "pillow>=13.0.0"- poetry
poetry add "pillow>=13.0.0"- uv
uv add "pillow>=13.0.0"
Severity breakdown
CVSS 4.0 0.0
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
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- None
- Privileges required
- None
- User interaction
- None
- Confidentiality (vulnerable system)
- None
- Integrity (vulnerable system)
- None
- Availability (vulnerable system)
- High
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
CVSS 3.1 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Weakness
CWE-409: Improper Handling of Highly Compressed Data (Data Amplification)
The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| PYSEC-2023-175 Pillow versions before v10.0.1 bundled libwebp binaries in wheels that are vulnerable to CVE-2023-5129 (previously CVE-2023-4863). | High Known exploited | Also affects pillow |
| GHSA-j7hp-h8jx-5ppr libwebp: OOB write in BuildHuffmanTable | High Known exploited | Also affects pillow |
| GHSA-78g4-xqwv-q3g8 Pillow: Bundled libopenjp2 2.5.4 in all wheels since 11.1.0 carries OSV-2025-219 heap-buffer-overflow write reachable from Image.open().load() | High | Also affects pillow |
| GHSA-654x-cwwv-5j9c Pillow: Arrow export leaks stale heap memory when PILLOW_ALIGNMENT > 1 | Medium | Also affects pillow |
| GHSA-xvh5-g6gv-559v Pillow: Memory disclosure and segfault in libtiff encoder via crafted TIFF tags | High | Also affects pillow |
| GHSA-g7cr-3p24-7wf7 Pillow: Heap buffer overflow writing JPEG comment after ICC profile fills buffer | High | Also affects pillow |
| GHSA-9v9v-9qvf-h2hj Pillow: Heap over-read in WMF/EMF rendering via 16-bit dimension truncation (Windows builds) | High | Also affects pillow |
| GHSA-g4qv-2jxx-769h Pillow: PNG eXIf chunk makes EXIF parsing run in quadratic time | Medium | Also affects pillow |
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