sqlmapproject/sqlmap · error · H2CompressionError

invalid HPACK header index 0

Error message

invalid HPACK header index 0

What it means

Error "invalid HPACK header index 0" thrown in sqlmapproject/sqlmap.

Source

Thrown at lib/request/http2.py:462

    def _add(self, name, value):
        entry_size = self._entry_size(name, value)
        if entry_size > self.max_size:
            self.dynamic = []
            self._size = 0
            return
        self.dynamic.insert(0, (name, value))
        self._size += entry_size
        self._evict()

    def _evict(self):
        while self._size > self.max_size and self.dynamic:
            name, value = self.dynamic.pop()
            self._size -= self._entry_size(name, value)

    def _get(self, index):
        if index <= 0:
            raise H2CompressionError("invalid HPACK header index 0")
        if index <= STATIC_LEN:
            return STATIC_TABLE[index - 1]
        dynamic_index = index - STATIC_LEN - 1
        if dynamic_index < 0 or dynamic_index >= len(self.dynamic):
            raise H2CompressionError("HPACK dynamic index out of range")
        return self.dynamic[dynamic_index]

    def decode(self, data):
        data = bytearray(_as_bytes(data))
        pos = 0
        headers = []
        list_size = 0
        saw_header = False
        while pos < len(data):
            first = data[pos]
            if first & 0x80:
                saw_header = True
                index, pos = decode_integer(data, pos, 7)

View on GitHub (pinned to 0a35b20e39)

When it happens

Trigger: Thrown at lib/request/http2.py:462 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/79e0757826150a00. Report an issue: GitHub.