vulnerability / NVI-00016126 / Revision 1
Pillow: Heap out-of-bounds write `Image.paste()` / `Image.crop()` via signed coordinate overflow
GitHub lists this reviewed advisory for Pillow. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
7.5 high
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
Pillow
source listed< 12.3.0
### Summary Pillow's public image coordinate APIs can trigger a native heap out-of-bounds write when given coordinates near the signed 32-bit integer limits. In 4-byte pixel modes such as `RGBA`, this becomes a controlled backward heap underwrite: for a source image of width `W`, Pillow writes `4 * W` attacker-controlled bytes starting `4 * W` bytes before the destination row pointer. With successful large image allocation, the theoretical upper bound is ~2 GiB backwards from the destination row. Minimal public API trigger: ```python from PIL import Image INT_MIN = -(1 << 31) src = Image.new("RGBA", (2, 1), (0x41, 0x42, 0x43, 0x44)) dst = Image.new("RGBA", (8, 1)) dst.paste(src, ((1 << 31) - 2, 0, INT_MIN, 1)) ``` The same root cause is also reachable through `Image.crop()` and `Image.alpha_composite()`. No private API, ctypes, custom Python object, or malformed image file is needed. This has been confirmed as an ASAN heap-buffer-overflow write. On normal non-ASAN Pillow builds, the minimal trigger corrupts the heap and aborts with `double free or corruption (out)` ### Details `src/PIL/Image.py:paste()` accepts a 4-tuple box and passes it to the native `ImagingCore.paste()
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
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04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
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- GHSA-6r8x-57c9-28j4 ↗
GitHub Advisory Database · vendor advisory
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Public revision history
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- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.