vulnerability / NVI-00016251 / Revision 1
Protobuf: Unbounded recursion depth in embedded-message decoding
GitHub lists this reviewed advisory for protobuf. 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.
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
protobuf
source listed>= 0.8.0, < 0.16.1
### Summary Unbounded recursion depth in `Protobuf.Decoder` (Hex package `protobuf`, versions `>= 0.8.0, < 0.16.1`) lets an unauthenticated attacker crash any service that decodes untrusted protobuf messages whose schema contains a self-referential or cyclic message type. A small request body (a few KB to a few MB) that nests an embedded field hundreds of thousands to millions of levels deep forces the BEAM to recurse once per level, exhausting memory and pinning a scheduler. A handful of such requests can take the node offline (a request-amplification denial of service). ### Details `Protobuf.Decoder.value_for_field/3` handles embedded message fields in its `embedded?: true` branch at `lib/protobuf/decoder.ex:218-243`. For an embedded field it calls `decode(bin, type)` recursively, which re-enters `build_message → handle_value → value_for_field`. The recursive call is not in tail position (its result is consumed by the surrounding decode after it returns), so every nesting level retains a live frame on the process stack and heap. There is no recursion-depth counter anywhere in the decoder. For any schema with a self-referential message type (e.g. `message Tree { Tree child = 1
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.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database
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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-rv48-qqj5-crxg ↗
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Public revision history
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- Revision 1 ·
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