← index #17817Issue #17818
Off-topic · high · value 3.161
QUERY · ISSUE

Assertion error on invalid string to compile()

openby jepleropened 2025-08-02updated 2025-08-02
bug

Port, board and/or hardware

unix port, coverage variant, x86_64 linux

MicroPython version

MicroPython v1.26.0-preview.521.g658a2e3dbd on 2025-08-02; linux [GCC 12.2.0] version

Reproduction

>>> compile("a\\\n", "", "eval")
micropython: ../../py/emitbc.c:356: mp_emit_bc_end_pass: Assertion `emit->stack_size == 0' failed.

Expected behaviour

Should throw a SyntaxError

Observed behaviour

crashes with an assertion failure

Additional Information

This crash was found by aflplusplus and minimized manually.

Code of Conduct

Yes, I agree

CANDIDATE · ISSUE

websocket crash on corrupt data

openby jepleropened 2025-08-02updated 2025-08-02
bug

Port, board and/or hardware

unix port, coverage variant, linux x86_64

MicroPython version

MicroPython v1.26.0-preview.521.g658a2e3dbd on 2025-08-02; linux [GCC 12.2.0] version

Reproduction

Run the following code:

import io
import websocket

# put raw data in the stream and do a websocket read
def ws_read(msg, sz):
    ws = websocket.websocket(io.BytesIO(msg))
    return ws.read(sz)

# a corrupt frame
print(ws_read(b"aa", 2))

Expected behaviour

An exception is raised because the data is not valid websocket data

Observed behaviour

micropython terminates with an assertion error:

micropython: ../../extmod/modwebsocket.c:97: websocket_read: Assertion `self->buf[0] & 0x80' failed.

Additional Information

Found with fuzzer, minimized by me

Code of Conduct

Yes, I agree

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