GBool GfxShadingBitBuf::getBits(int n, Guint *val) {
  int x;

  if (nBits >= n) {
    x = (bitBuf >> (nBits - n)) & ((1 << n) - 1);
    nBits -= n;
  } else {
    x = 0;
    if (nBits > 0) {
      x = bitBuf & ((1 << nBits) - 1);
      n -= nBits;
      nBits = 0;
    }
    while (n > 0) {
      if ((bitBuf = str->getChar()) == EOF) {
	nBits = 0;
	return gFalse;
      }
      if (n >= 8) {
	x = (x << 8) | bitBuf;
	n -= 8;
      } else {
	x = (x << n) | (bitBuf >> (8 - n));
	nBits = 8 - n;
	n = 0;
      }
    }
  }
  *val = x;
  return gTrue;
}

This weakness involves numeric computation errors, such as integer overflows, underflows, or precision losses, which can lead to miscalculations and exploitable behaviors in software.