XTLS/Xray-core · error

invalid padding length

Error message

invalid padding length

What it means

Error "invalid padding length" thrown in XTLS/Xray-core.

Source

Thrown at proxy/hysteria/protocol.go:52

	bReader := quicvarint.NewReader(r)
	addrLen, err := quicvarint.Read(bReader)
	if err != nil {
		return "", err
	}
	if addrLen == 0 || addrLen > MaxAddressLength {
		return "", errors.New("invalid address length")
	}
	addrBuf := make([]byte, addrLen)
	_, err = io.ReadFull(r, addrBuf)
	if err != nil {
		return "", err
	}
	paddingLen, err := quicvarint.Read(bReader)
	if err != nil {
		return "", err
	}
	if paddingLen > MaxPaddingLength {
		return "", errors.New("invalid padding length")
	}
	if paddingLen > 0 {
		_, err = io.CopyN(io.Discard, r, int64(paddingLen))
		if err != nil {
			return "", err
		}
	}
	return string(addrBuf), nil
}

func WriteTCPRequest(w io.Writer, addr string) error {
	padding := hysteria.TcpRequestPadding.String()
	paddingLen := len(padding)
	addrLen := len(addr)
	sz := int(quicvarint.Len(uint64(addrLen))) + addrLen +
		int(quicvarint.Len(uint64(paddingLen))) + paddingLen
	buf := make([]byte, sz)
	i := varintPut(buf, uint64(addrLen))

View on GitHub (pinned to 7d214f8b09)

When it happens

Trigger: Thrown at proxy/hysteria/protocol.go:52 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of XTLS/Xray-core@7d214f8b09 (2026-08-15). Data as JSON: /api/errors/39f411f9d1b22ff8. Report an issue: GitHub.