vulnerability / NVI-00015253 / Revision 1
libp2p: yamux connection DoS via oversized data frame
GitHub lists this reviewed advisory for libp2p. 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.
libp2p
source listed<= 0.7.0
### Summary The yamux stream multiplexer in py-libp2p does not validate incoming DATA frame lengths against the receive window before reading the frame body. Any peer that completes a standard libp2p handshake can send a single 12-byte frame claiming a 4 GB body, causing the victim's yamux read loop to block indefinitely. This affects the default `new_host()` configuration and requires no special setup on either side. ### Details In `libp2p/stream_muxer/yamux/yamux.py` (lines 915 to 926), the `handle_incoming()` method dispatches on frame type. When a DATA frame arrives, it reads the body unconditionally: ```python elif typ == TYPE_DATA: try: data = ( await read_exactly(self.secured_conn, length) if length > 0 else b"" ) ``` The `length` field is taken directly from the wire-decoded frame header, a 32-bit unsigned integer with a maximum value of 4,294,967,295. There is no check that `length` fits within the stream's receive window (`DEFAULT_WINDOW_SIZE = 256 * 1024` bytes). The body read also happens before the code checks whether the referenced `stream_id` even exists in `self.streams` (that check is at line 954), so any s
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-hmj8-5xmh-5573 ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
Public revision history
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- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.