sqlmapproject/sqlmap · error · H2CompressionError

truncated HPACK string payload

Error message

truncated HPACK string payload

What it means

Error "truncated HPACK string payload" thrown in sqlmapproject/sqlmap.

Source

Thrown at lib/request/http2.py:428

def encode_string(value, huffman=True):
    value = _as_bytes(value)
    if huffman:
        encoded = huffman_encode(value)
        if len(encoded) < len(value):
            return encode_integer(len(encoded), 7, 0x80) + bytearray(encoded)
    return encode_integer(len(value), 7, 0x00) + bytearray(value)


def decode_string(data, pos):
    if pos < 0 or pos >= len(data):
        raise H2CompressionError("truncated HPACK string")
    use_huffman = bool(data[pos] & 0x80)
    length, pos = decode_integer(data, pos, 7, max_value=MAX_HEADER_BLOCK_SIZE)
    end = pos + length
    if end > len(data):
        raise H2CompressionError("truncated HPACK string payload")
    raw = bytes(data[pos:end])
    return (huffman_decode(raw) if use_huffman else raw), end


class Decoder(object):
    def __init__(self, max_size=4096, max_header_list_size=MAX_HEADER_LIST_SIZE):
        self.max_allowed_size = max_size
        self.max_size = max_size
        self.max_header_list_size = max_header_list_size
        self.dynamic = []
        self._size = 0

    @staticmethod
    def _entry_size(name, value):
        return 32 + len(name) + len(value)

    def _add(self, name, value):
        entry_size = self._entry_size(name, value)

View on GitHub (pinned to 0a35b20e39)

When it happens

Trigger: Thrown at lib/request/http2.py:428 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of sqlmapproject/sqlmap@0a35b20e39 (2026-08-26). Data as JSON: /api/errors/b9097692b9aae7a8. Report an issue: GitHub.