vulnerability / NVI-00016124 / Revision 1
Pillow `BdfFontFile`: `Image.new()` called without `_decompression_bomb_check()` — bomb protection bypass via font loading
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 `PIL/BdfFontFile.py` `bdf_char()` (lines 84–88) reads the `BBX width height` field from a BDF font file and passes the dimensions directly to `Image.new()` without calling `Image._decompression_bomb_check()`. This completely bypasses Pillow's documented decompression bomb protection. `Image.open()` enforces `MAX_IMAGE_PIXELS = 89,478,485` and raises `DecompressionBombError` for images exceeding `2 × MAX = 178,956,970` pixels. The BDF font loading path calls `Image.new()` directly, which only calls `_check_size()` (validates `>= 0`) — no pixel count limit. **Vulnerable code (`PIL/BdfFontFile.py` lines 84–88):** ```python # width, height from attacker-controlled "BBX width height x y" line try: im = Image.frombytes("1", (width, height), bitmap, "hex", "1") except ValueError: # TRIGGERED when BITMAP section is empty (zero hex lines) im = Image.new("1", (width, height)) # ← NO _decompression_bomb_check()! # ^ This image is stored in self.glyph[ch] — persists in memory ``` **Attack trigger:** A BDF glyph with `BBX 20000 20000` and an empty `BITMAP` section causes `Image.frombytes()` to raise `ValueError`, then `Image.new("1", (20000, 20000))` allocates *
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-45hq-cxwh-f6vc ↗
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.